The term "Battles" for this category includes all conflicts of any reasonable size. For perspective, a fight between 5 or fewer total combatants would normally be excluded from this list. That said, conflicts also may vary in size and scope.
For example, the Battle for the Old World may have only included 2 titan lords (Ursegor and Ismael), in which case it would normally be excluded. However, its scope was immense, devastating the northern continent and resulting in an unknown, but presumably high, number of casualties.
Note that although the Dark Wave is more of an event than a battle, it has been included in this category because of its significance and range of impact.