Caius, The Watcherdemon gains additional health and damage on Challenge Level 1 and above, but has the same appearance and behavior as before.
- Shadow Swords. Caius will summon 4 large swords in quick succession from above his head, the swords travel towards the player in a straight line and will deal 14 damage to the player is touched.
- Shadow Wall. Caius will summon a vertical beam in front of him (similar to the Wicked's attack found in The Byfrost) that will travel towards the player at high speed, it deals 20 damage to the player if touched.
- Shadow Sliver. Caius will summon an enemy (very similar to the Slivers found in Deep Jungle challenge levels) that will follow the player at high speeds and deal 8 damage upon touching the player, they have approximately 2,000 health. Multiple Shadow Slivers can be summoned, the maximum amount is currently unknown.
Base your attacks and defenses by his 3 moves and tells.
His most common move is the Shadow Swords, he will start raising his hand. If you are attacking by melee than you should move back to dodge the swords, you probably want to move back far enough where you don't have to weave between them. If you are attacking with magic or guns just dodge or move back.
His second move is the shadow wall. Though not as common as the Shadow Swords and Shadow Sliver it can be devastating if you are using melee. If you are fighting with melee you need to watch out for his tell. He will suddenly lunge forward. Make sure you know how to dash or use speed. Immediately go away from him until the wall finishes. I do not advise trying to avoid it.
His final move Shadow Sliver is the most important when fighting him. When you see him seem to cup a dark orb it is your main chance to attack. At the other times try and get a few hits in but now go for the full attack. Him summoning the Shadow Sliver takes a few seconds and he will recover standing still for a few seconds. But as good as this moment is to attack it will go horribly if you are overwhelmed by the shadow slivers. If you concentrate on him every time he summons them soon you will be overwhelmed by them, they will change from the near harmless 1 by 1 creatures to a destructive mass. When this happens get far away from Caiuses and concentrate on destroying all the Slivers. The Slivers will catch up to you while Caius will have a harder time.
As a last few suggestion. If you are lower then 50 health, HEAL! You won't realize how fast 50 health will go by and you are on the ground because you are dead, this goes for all fights that aren't one shot kills and not difficult. And finally I suggest moving away from him slowly while fighting and only come back when he's summoning. When you get to the portals turn around, don't get cornered. and just keep going in the opposite direction. This boss is also much easier with a ranged weapon. Typically speaking melee builds will have a much harder time with this boss unless they are using a weapon like Ringabolt's Axe, or any other ranged melee weapon.