Damage cancel

This section or article refers to a topic which has been made obsolete in-game. Damage cancel no longer occurs on Ephinea. This article remains for archival and preservation purposes only.

Damage cancel in action – note the Gibbles's health bar

Damage cancel (DMC) is a PSO community term describing the following process:

• A player attacks an enemy, producing any damage number (including 0) or inflicts a status effect (including Jellen & Zalure).
• The player's game client sends to the server a data packet containing the total damage done to an enemy, which is calculated as its max HP minus its current HP.
• The server forwards the damage packet to all other players. Receiving clients will accept that value and update the monster's HP no matter what. The value could be higher or lower than what the local client sees, because it's possible an action happened on another client that affected the monster's HP.
• However, the server relays the most recently received data packet no matter what, regardless of whether its total is higher or lower than any other data. Therefore, if two people damage an enemy at roughly the same time, one of the two totals may overwrite the other, effectively negating one of the two players' damage.
• This manifests as an enemy under massive attack from multiple players taking far less damage than expected. As an extreme worst-case example, an enemy being hit by rapid fire weapons (e.g. Last Swan) doing 0 damage per hit can be rendered nigh-invincible to the other players.
• ATA misses do not send damage packets, but specials failing to activate do cause a damage packet to be sent.