Osiris is a common raid boss enemy.
Note: The following skill list includes all skills listed in Sister's Codex page. However, this list does not necessarily encompass all of her attacks. See Combat Behavior for more detailed information.
- Emperor: Osiris attacks the nearest enemy.
- Punish: Osiris summons the Eye of Punishment, which will fire a laser beam when fully charged. Damage taken by the Eye of Punishment is greatly reduced when Super Armor and Shield are active.
- Sandstorm: Osiris summons a sandstorm, which draws in nearby enemies.
- Nightmare - Judgement: Legends say that Osiris can summon the Eye of Judgement, bringing about the end of the world when it is fully charged.
Contrary to the description, Emperor consists of 3 wide-area melee strikes and a bombardment attack (creates a damaging explosion at every player's location). He can interrupt this sequence with any other move, after which he will continue the combo from where he was previously.
Osiris also uses an unlisted ranged attack when every player is outside the range of Emperor. He will keep using this attack in quick succession until at least one player returns in range of his melee strikes.
- Staying in melee range for the entire duration of the fight is highly recommended.
- When he uses Sandstorm the tornadoes will always leave a safe zone in the center of the arena.
- The 3rd hit of his Emperor combo is always a 360° strike that hits everything around him.
- Destroying the Eye of Punishment is optional as they only attack with a rotating laser beam.
- Despite the scary name, Nightmare - Judgement is never used in the Co-op raid battle.