Assault Battles are a special type of event that require you to play through 8 waves of enemies. Each Assault Battle features a different faction of enemies and requires you to use a different faction of characters to defeat it. Assault Battles have multiple tiers: Tier I (Hard), Tier II (Very Hard), and Bonus Tier. Each tier is a harder version of the previous one with identical enemies that have higher levels, gear levels, health and damage. Some Assault Battles have a fourth tier known as the Mythic Tier. Mythic Tier will be significantly harder than previous tiers and may have different enemy compositions for waves. Victory counts are not shared between the tiers and Tier I and Tier II are able to be refreshed. Assault Battles events run for 24 hours. Each Assault Battle has a special ability that characters can use, this ability sometimes changes dependent on the character's faction.