Self Damage is damage dealt by a character to themself as an effect or cost of an action, typically an Attack. Self Damage serves to provide a risk, limitation, or drawback to an action, and as such it is frequently associated with powerful abilities. Self Damage is typically only applied to damage that stems exclusively from an action, not from environmental hazards such as Fall Damage or activation of traps (even when self-inflicted by player action).
Self Damage is often seen with Area of Effect Attacks, which may damage the user in the same way they damage enemies. In these cases it sometimes overlaps with Friendly Fire. Self Damage may be dependent on an Attack landing, but it may occur irrespective of whether the action hit any given target. One subtype of Self Damage is Death As a Cost, wherein an action causes the instant death of a user.