Filler Battles

As the name implies, Filler Battles are minor scenarios that have little to no impact in the main plot of a particular franchise. They often involve skirmishes against raiders, bandits, and other miscreants. Sometimes, the purpose of these battles is to act as exposition, fleshing out a character's background and personality. But in most cases, they're used for filling in stages for particular officers who've participated in less major battles than the rest.

Dynasty Warriors
Battles that fit this category of interest for this series are the ones which have little to no historical mention or importance for the era.

Dynasty Warriors 3 has three minor battles found only in Musou Mode. These stages are mostly small and compact, yet they provide players enough room to hone their skills and gain stat bonuses with ease even in Hard Mode.

In Dynasty Warriors 4, these battles appear in the form of optional scenarios that take place before any major chapter stage. While finishing them is not required, their completion often results in granting several advantages for the player's side such as minimizing ambush attacks, deploying siege weapons from past battles, etc.

The spin-off Empires titles and Dynasty Warriors Next includes miniature optional quests featuring the aforementioned tasks throughout their playthrough experience.

Samurai Warriors
Certain playable characters (mostly the women) in Samurai Warriors 2 have at least one stage where they must save a village from bandits or eradicate pirates. Depending on the officer being used, other characters may appear to aid players or hinder them instead.

Kessen
Kessen has filler battles in the form of the escape sequences. Although the player can plan to win or lose the chase at their whim, the end result of the chase is determined by the main battle which took place before it.