This genre is for the Musou/Musō (E.g. Dynasty Warriors) type of "hack & slash" and not the ARPG kind, which should already be covered by Action RPG.
Hack and Slash gameplay requires quick moves and devastating attacks to take out massive hoards of enemies relatively quickly. Swords or other melee weapons are typically used, but projectile based weapons may be present. Combat and violence is usually emphasized above all other game or plot mechanics. A dodge mechanic may not always be present, as the player is expected to repeatedly "hack away" at their opponents.