Debuffs can do a number of things weaken their stats, stop them from acting, and etc.
These debuffs weaken whoever is under their effects.
Damage over Time
DoT debuffs do damage for their duration.
CC debuffs stops an enemy from acting, using a skill, or disrupts an enemy's skills.
Frost and Frozen/Freeze
Stun and Knockdown
|These two debuffs prevent a hero/enemy from acting for a short period of time. It can also be used to interrupt skill casting.|