The continuing trend in the Dynasty Warriors series is the difficulty of defeating Lu Bu, regardless of stats, weapons, difficulty, or moveset. Just a side note that if one is to even go near Lu Bu, it is highly recommended that you have at least a third level weapon with five 
attacks, a high defense, and a relatively high offense. However, not every player of the game has the time to level up or get a powered up weapon or stats before the Hulao Gate stage (which often occurs fairly early in many a Musou Mode playthrough), rendering players unable to even go near him without being killed right away (this is why in the novel it took the combined efforts of the three sworn brothers just to drive him off). This guide shows methods on how to defeat Lu Bu with any weapon, skillset, stats, and moveset. The concept of defeating is the same: Avoid him announcing you, avoid hand to hand combat, and avoid him entering into a high morale state.
In Dynasty Warriors 4, if Lu Bu requests a duel and you're not powered up, deny it, as there are no easy-win methods to defeating Lu Bu in one-on-one combat. In Dynasty Warriors 6, it's nearly impossible to challenge him until your character is at least leveled in the late tens or twenties. If not highly leveled, use hit-and-run tactics, grapple attacks, or even a powerful horse and run towards him. At the Battle of Xiapi, you are forced to face against him as he is the main enemy commander of the stage. The easiest way is to steal his horse when he is off it. It is very strong and fast, so just keep riding by him and unleashing your Musou Attack. However, events at Xiapi can cause Lu Bu's morale to plummet, giving you an advantage and at the same time, preventing allies from dying offscreen regardless of Lu Bu's own morale apart from his overall army.
It is also advised in most if not all installments to combat him alongside allies, be it a swarm of NPCs or a second player, so it can be hard for Lu Bu to retaliate and/or to watch for any planned sneak attacks should his aggro be focused on someone else.
Hu Lao Gate (Dynasty Warriors 3)
Note that in this game, Lu Bu will relentlessly chase down the player should he come into contact with them; his two sub-officers, Zhang Liao and Gao Shun are also a clear indicator of his proximity as they often follow Lu Bu very close despite not being mounted.
Method 1
Pursue him and do the hit-and-run technique. Don't kill Diaochan beforehand, and it takes about 10 minutes to deplete his HP. This game has arguably one of the more easier Lu Bu battles, due to the fact that his attacks are more easier to telegraph and are not as wild and absurd. His C1 is easy to simply jump over, but it is bound to knock anyone off their horse due to the quake physics.
Method 2
However, if one also has enough arrows, they can snipe him, though unlike other officers with an encounter intro, Lu Bu will always have his defenses increased regardless of encountering the player onscreen or not. Stay out of his view if possible to snipe him if he is not surrounded by units which can block your arrows, friendly or hostile.
Method 3
Another notable strategy depending on the character, is to exploit the red health state and play hit-and-run with Lu Bu in order to spam your True Musou Attack on him, since your Musou bar when on low HP replenishes on its own. Normally, doing this against many enemies will often catch them out when they try to attack you; in Lu Bu's case, since he has one of the fastest running speeds in the game and can catch up to you easily each time he is often forced to stop and attack you if you keep running and jumping from his attacks in a timely manner. Repeating the True Musou Attack strategy on him enough will ensure victory.
This hit-and-run method is the easiest method as with any tough officer, requiring very little skill or game experience/fighting ability to carry out, and does not require any character leveling up. However, some characters may or may not have good True Musou Attacks due to the aerial damage penalty despite the automatic fire element so the process may take more longer with them.
Hu Lao Gate (Dynasty Warriors 4)
Method 1
This is the same as the third method above, but with some twists. First off, it is wise to deny Lu Bu's duel whenever. It also carries less risk due to Lu Bu's brand new C1 attack, which is an unblockable grab that can hit multiple targets at once nearby. However, unlike his old C1, this attack does not cover all around Lu Bu and can easily be parried if timed right. It will also fail on airborne targets it connects on and is still a rather sluggish move, so like his old C1 it can easily be jumped over.
Method 2
Wait directly in front of the gate while the ram is attempting to breach it. Once the gate opens, immediately run into the inner castle, and wait at the right-hand-most corner of a wooden fence. Lu Bu will appear directly where you're standing. The second he appears, knock him down. Do this immediately, as once his scenario plays, he will most likely enter a high morale state. If your character is powered up, a good majority of his health will be eliminated, making your job a lot easier. If you have not yet evolved your character, you can get the easy advantage by continuing a combo on him after the scene plays.
Method 3
Lure Lu Bu directly in the middle of your forces. Do not worry about any sub-generals being killed, as it really makes no difference, and go ahead and defeat Diaochan. Lu Bu will not go into a frenzy if you do this. Stay away from Lu Bu's sight (as in the Dynasty Warriors rule of thumb: if you can't see it outside of the processing range, it's not happening or is happening in a different way) for approximately 10 minutes while hacking and slashing other generals. Once Dong Zhuo's the only one left, you can safety go back to deal with Lu Bu. By this time he is in his hyper state, your aforementioned actions involving the elimination of all other enemy units will contribute to the overall morale of Dong Zhuo's army lowering, giving you a major advantage and preventing high-morale allies outside of the processing range from dying out of the blue; even then, Lu Bu himself will remain at maximum morale even if his soldiers are all defeated, but he will not be able to rapidly decrease allies' morale offscreen due to his own army's morale being very lopsided against him.
Method 4
You will need all eight bodyguards, maxed out, and at least a level 4 weapon but for experts a level 2 weapon would be enough. Do not accept the duel he requests. Lure him to your bodyguards and they will attack him. Recharge your Musou gauge while they are busy fighting and use your Musou Attack on him. Keep doing this and you will defeat Lu Bu. Having maxed out bodyguards for this helps to make sure you always have allies on hand that will not die so easily on you, as well as more aggressive ones.
Method 5 (only for Duel Mode)
To defeat Lu Bu in a duel, you should use characters with an elemental shot C1 attack. Examples are Cao Cao, Zhuge Liang, Pang Tong, Jiang Wei, Sima Yi and more, though some characters fire it faster than others. However, this works with any solid projectile C1 character overall (like Huang Zhong and Xiahou Yuan). Pressing 
and properly connecting with each one will allow you to zone him out and chip away at his HP if done properly. You need that character to be fairly maxed out or the process will take too long to finish the duel. You also need to be mindful of your spacing, for Lu Bu will always block if he's in the correct distance from you. Thus, any setting where multiple projectiles can be fired at once can easily cause enough blockstun on him to force him out of the blocking distance and to take the rest of the volley. Outside of duels however, it can be easier if he's surrounded by the whole chaos of the battlefield, such as any allies swarming him, but you have to be mindful about getting interrupted by other enemies and/or having your projectiles get blocked by any other units; allied or enemy.
Another strategy akin to this one is to use Huang Gai's C1 attack upon reaching each wall of the arena as Lu Bu is chasing you, allowing you to launch him fairly high and to loop damage on him with gradual fire-based damage until he's almost dead.
Si Shui Gate (Dynasty Warriors 5)
Method 1
Upon encountering Si Shui Gate, Lu Bu appears. Do not engage Lu Bu, but rather stay off of the bridge. If you haven't already, go to gates and break the boxes to get arrows. Do this until you have about 80 arrows available. Go back to Si Shui Gate, remaining off the bridge, and out of Lu Bu's sight. Defeat any remaining officers that are out of the bridge, including Lu Bu's officers in an attempt to lower morale. Li Ru should appear with reinforcements in the detour winding towards Si Shui Castle, but if one has bodyguards placed at a point in the road, it shouldn't be a problem.
Once every officer and general is taken care of, position yourself exactly with Lu Bu, and repeatedly snipe him with your arrows. Do not use Musou arrows in an attempt to defeat him quicker, for it will only waste arrows. Once he gets up, he will engage you. Run far from the base of the castle to avoid detection (if he doesn't announce you, you're undetected). Once you are out of the chase, go back and use a charge attack arrow shot to stun him, then use normal arrows to fire at him when he's stunned. Do this while off the bridge, or he will spot you, and go into hyper rage, making him impossible to defeat with a non-leveled up weapon. However, if Lu Bu happens to be blocked/clustered by a lot of other units, ally and enemy alike, it may be difficult to make sure your arrows connect, so don't forget to reposition as often as needed.
Eventually, if you shoot him on target with all 80 arrows using strategic combinations, he should be defeated. If really confident, you could go up and slay him with your weapon, but do it quickly, for when struck, he will go into a Musou Rage when near death, probably killing you in one shot.
Hu Lao Gate (Dynasty Warriors 5)
Method 1
Once all the enemy officers are defeated outside the castle, grab a Musou Rage after the hundredth kill if you happen to have your fourth weapon equipped, or hold onto your Musou Rage that you might have collected earlier. Do not engage the enemy gate captain closest to Lu Bu, or the method will not work. Once all gate captains, enemy generals, commanders, etc. are dealt with outside the gate, defeat the aforementioned gate captain. Immediately following the opening of Hu Lao Gate, step inside, and direct your character to the left hand side directly in the door (this is where Lu Bu will be positioned). Right before Lu Bu comes, go into Musou Rage mode, and once he comes, knock him off his horse, and use a Musou Attack, and juggle him at least five times. He will now be dead, and he does not even get a chance to go into any possible hyper state.
Another method is to bog him down with allies and as soon as he enters his rage, simply stand back and watch until it wears out. If you don't want your allies to die on-screen, then make sure you flee the area for a while so the visual processing no longer applies; this is often safe when all of your allies have fairly high morale if not, morale for each independent unit that exceeds Lu Bu's.
Method 2
For a more challenging method, once at the gate, ignore the main gate, and go directly for Zhang Liao. Defeat Zhang Liao, and get any power up items before you engage Lu Bu. Defeat the enemy gate captains past the gate in the enemy main camp, and do not go near Dong Zhuo, for you will trigger Lu Bu coming to his aid. It is generally wise to have a Musou Rage at this point, for it's not the difficulty of defeating Lu Bu, but his freakishly high defense that makes the battle long and tedious.
Once Dong Zhuo announces for Lu Bu, zig-zag directly towards the gate, and knock Lu Bu off his horse, follow up with a Musou Attack, go into Musou Rage, and juggle him as long as you can, with as many repetitions as you can. Do not let Lu Bu go near Dong Zhuo, for this will trigger Lu Bu's attack boost state, and make it almost impossible to engage Dong Zhuo directly with a weapon. Once Lu Bu gets up, he should be at about half in damage. Stun Lu Bu somehow and power up the Musou gauge while he's busy recovering. Once Lu Bu gets up, juggle him, and pull out a Musou Attack, get up and immediately fill up your gauge. Attack Lu Bu with rapid C2 attacks (, ), hurling him in the air, and juggle him (but be mindful if he somersaults out of it past the first or second one). Once your Musou gauge is filled up, use a Musou Attack on him.
With a level one weapon, Lu Bu should be about eight-tenths dead. Once he recovers, shoot him with a stun arrow immediately, and charge up your Musou gauge. Lu Bu will likely go down in about one more good power move, so after this, engage him once more with a Musou Attack or strong combo and you should defeat him.
Method 3
If you want to, you can challenge yourself and equip every item devoted to offense (such as a maxed out Tiger Amulet, Green Scroll, and True Way of the Musou if you are doing this stage in Xtreme Legends), and try not to get hit. This is arguably the most challenging method but probably the fastest, considering every item would contribute to damage dealing. As long as you use the correct string of attacks (most suited for your character of choice, of course), you will defeat him in mere minutes without the long process of the other methods.
Method 4
Spam C3 combos on him, and it will be easier if you and your allies corner him. Just don't let your allies steal your kill if you need it. However, this must be done with fairly high attack stat or Lu Bu will not flinch; if you manage to stun or stagger him into a juggle state, then for sure aggressive allies will help join in on the fight and juggle him to death alongside you.
Hu Lao Gate (Dynasty Warriors 6)
Method 1
Before Lu Bu appears, take the ladder and climb the wall when you have to destroy the ballistas. Ignore the ballistas (if you destroy them, the breaching will happen way too fast and Lu Bu will appear too soon) and kill all officers inside the Hu Lao Gate (so Lu Bu cannot get any assistance). Do not attack Dong Zhuo or the plan will not work. When Yuan Shao has already breached the one of the gates, Lu Bu will appear. Use your Musou Attack to fight him. If you run out of Musou, stay away from Lu Bu and charge your Musou so you can prepare to use it on him again, then rise and repeat.
The easiest way is to ram him with your horse. Maximize your mount, preferably with Ice-powered element and watch him fall after a few rounds of charging.
Hu Lao Gate (Dynasty Warriors Advance)
Method 1 (Shu scenario)
Once you get him to appear in the battlefield, you will be informed to lure him into a trap. Do follow the plan and let two of the three officers harm him. Then, when the third one engages in, take a chance on him. By now, Lu Bu will be too weak and may not have soldiers around him, so he can be dispatched with a couple of prepared C3 combos. And it will award you the Sky Piercer either way!
WARNING: If you allow the third officer to last longer than one turn against him, he will retreat and you won't be rewarded for defeating him.
Method 2
If you have choose to not fight for Shu, his battle will be much trickier. First of all, be sure to save your Musou for this single battle. Second: DON'T PURSUE LU BU (if you're in the "arena" with him). Instead, dispose of his troops, using C1, C3 and C4 attacks while avoiding Lu Bu's offense. It will be hard, because his troops have absurdly high health and stats for a common archer, spearman or swordman. But, once you dispatch them, lure Lu Bu in using C1 toward you or block the beginning of his attack strings. At this point, unleash your Musou and see him fly. Be sure to not be around him when your Musou ends. Afterwards, use C1 (to knock him down if you need some distance and your character has a "multi-hitting knock back attack in their C1) and prepared C3 (use it before he is too close or before he gets up) to catch him unguarded, then repeat C3 until he can't get up. This takes some luck, because his Hyper Armor sometimes negates one or two charge attack hits.
Survival Mode (Samurai Warriors)
Lu Bu is the last boss in the Abyss Survival Mode in Samurai Warriors and its expansion. It is highly recommended to equip items with 50+ buffs and at least a fourth weapon (or a strong third) for the fight. He rivals Oichi in attack range and can kill nearly any character in three or two hits. His weapon has the Thunder element which can possibly stun you or break your guard. He will usually win any deadlock and thus kill you with the following special attack animation. However, he no longer has his powerful grab-based C1, despite his model and whole moveset being from Dynasty Warriors 4 - it instead reverts to his old DW3 C1, which was his taunt.
The safest way to beat him and to not put the previous twenty-eight floors to waste is to abuse your character's True Musou. Run around the room, avoid being trapped in a corner, and let him have it. A higher Potence skill level helps but isn't necessary. Avoid clashing with his attacks and take advantage of your character's evade if he strikes. Be careful to avoid getting too close to his back as he can hit you on the last part of his first strike.
Alternatively, the gutsier method is to slowly chip away his life with half-finished combos (i.e.: , , ) or with attacks that break his guard. This method has a small chance of success with quick attacking characters like Hanzō, Kunoichi or Nobunaga. This is only recommended for players who are very good at predicting Lu Bu's AI and attack speed.
Dynasty Warriors 7
In the Wei, Wu or Shu storylines you will have to fight Lu Bu at Hu Lao Gate. The best way to fight Lu Bu is to use the Twin Axes (which you can purchase from Weapons Dealer). The main reason as to the Twin Axes is its C3 attack can temporarily stun him and is also the only attack (other than Musou Attacks) that can break his high defense fast enough. If continued Lu Bu will eventually be defeated.
You can also defeat him by using a Bow with an Ice element on a horse, which will prevent Lu Bu from running away. However, this method won't work at Dong Zhuo's Trap stage.
Dynasty Warriors 8
Lu Bu only poses a major threat if he is powered up, as this increases his damage and defense considerably. Encountering him without such power ups such as at Puyang, Xiapi, Ambition Mode or in most of the free mode battles against his forces in the Xtreme Legends expansion will allow you to fight him as you would another playable officer.
Lu Bu's most threatening appearance is at Wei's first stage at Luoyang, where he cannot be launched or comboed, and his attacks and defense will literally tear through your life in a single hit or two if you're not careful. Using a weapon that is either of the same affinity or of superior affinity will cause him to automatically guard frontal attacks in the higher difficulties. With this, the simplest way to defeat him is to pick a weapon that can efficiently use Cyclone (which damages opponents for blocking) and/or Slash (which will occasionally do a large chunk of damage to officers). Because Cyclone and Slash deal damage by percent, Lu Bu will take a high amount of damage without tedious attacking. To kill Lu Bu the quickest or most efficiently, there are multiple weapon attacks that are available. The Bow and Rod's, Dual-blade's, Throwing Knives', Boomerang's, Twin Axes', Striking Sword's and Nine Rings Blade's respective C6s will do large chunks of damage with a high consistency using Cyclone and Slash.
His midair Musou Attack is unblockable and depletes your entire lifebar if you haven't maxed out your defense in Ambition Mode, so you must use your own Musou as a reversal if you are stunned by his. Alternatively, if he uses the Musou, but you aren't stunned, it is possible to use the temporary invincibility frames of a switch attack, initiate a Storm Rush or to simply run out of range. His new grounded Musou Attack is a grab that flattens you out or increases his own defenses.
If, for some reason, you try to go in without Cyclone or Slash, be prepared for a very long battle. The only things that can knock Lu Bu into the air are EX attacks and the Shadow Sprint weapon actions, but it hardly matters given how you can't combo him while he's in the air. On Ultimate difficulty, the AI of playable officers against weapons of inferior affinities will only make them guard when you're in Rage mode; otherwise they WILL attack you with the moves that you can't use a Switch counter on. If you manage to land a C4, C5 or C6 on them, they will automatically perform a Storm Rush. Using a weapon of superior affinity and will be your fastest method to defeating him as you do more damage, while also being able to use a Storm Rush yourself. Otherwise, be prepared for the longest battle even with your maxed out attack.