Damage cancel

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 enemy's current remaining HP.
• The server relays its most recently received "remaining HP" packet back to all players except the one who sent it.
• 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 send HP 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.

Mitigation Strategies

• Pay close attention to damage output vs. teammates' and switching target if a teammate's DPS against the same target is superior.
• Kill an enemy in one hit (via Megid, Hell, or a one-shot attack e.g. Dark Flow) - this sends a data packet that the enemy is Dead, which cannot be overwritten.
• Cease firing Devil's/Demon's weapons once the target's HP has reached the lowest it can go.
• Know Technique strengths/weaknesses; don't spam AoE techniques e.g. Gifoie if they are ineffective at killing the target.
• Try to cast Jellen and Zalure on a target only once; judge case-by-case whether the enemy needs J/Z at all.