Damage Increase is a buff that increases the damage your heroes can inflict.
While in the battle, you can tap and hold the Buff icon and read what it does.
Here's a list of heroes who can apply this effect:
  • Emily (Leadership Ability)
  • Victoria (Passive Ability)
  • Eric Shieldbreaker (Ability 2)
  • Niya (Ability 3)
  • Solius (Leadership Ability and Ability 3)
  • Hardorc (Ability 3)
  • Zerra (Ability 1)
  • Maar (Ability 3)
  • Dieselrog (Ability 3)
  • Garn (Passive Ability)
  • Nightiel (Ability 3)
  • Kiana (Ability 3)
  • Telias (Ability 3)
  • Teenty (Ability 3)
  • Old Loor (Ability 3)
  • Rin the Unseen (Ability 3)
  • Master Duo (Ability 2)
  • Kin Li (Ability 2)
  • Hilda (Ability 2)
  • Kang Xi (Ability 3)
  • Lake (Ability 3)
  • Lei Zi (Ability 1)
  • Kulai (Ability 3)
  • Boreas (Ability 3)
  • Hera (Leadership Ability)
  • Revol (Passive Ability)
  • Yogi (Passive Ability)
  • Bordwin (Ability 3)
  • Hell Kitty (Ability 3)
  • Nelly (Ability 3)
  • Bar & Rel (Ability 3)
  • Keb & Bab (Ability 3)
  • Ace & Sin (Ability 3)
  • Wizz & Ard (Ability 3)
  • Slinger (Passive Ability)
  • Puncherface (Ability 2)
  • Shaiya (Ability 3)
  • Buff (Ability 2 - one of the possible buffs)