Only some of zombie hero rooms can activate this event gameplay. Click on the room and if you see the 'NEW' icon in the left corner of the map image, it's the room that has Zombie Hevo Division. In this gameplay we have:
Human: All humans will become heroes, and can use a new ability 'Boost Jump' (like the one in Item Battle)
Zombie: You will have 2 ~ 4 clones when you become zombie, you can summon them or order them to attack
Also there is no limit on using abilities for both zombie and human. Kill a zombie and it'll refresh your 'Deadly Shot' and 'Dead Run' ability
Music: Ninelie (Koutetsujou no Kabaneri OST) - Nightcore