Dagannoth Prime is the Magic-based Dagannoth King found in the depths of the Waterbirth Island Dungeon, along with fellow Dagannoth Kings, Dagannoth Rex and Dagannoth Supreme. Prime is the only monster to drop the Seers ringand Mud battlestaff. He, along with the other Dagannoth Kings, can also drop the dragon axe.
If players get too close to Dagannoth Rex when they are fighting Dagannoth Prime, Dagannoth Rex switches his aggressiveness towards them. This can be avoided by staying on the western part of the arena, as Rex will rarely (if ever) go there.
Dagannoth Supreme respawns while fighting Prime. This can be avoided by staying in the northeastern part of the arena by the seaweed. Players will want to use the "Long-Range" style with their Ranged combat unless the player is sure that they will not get the attention of Supreme.
Prime, along with his fellow king Supreme, have a very long-ranged attack. This means, if he targets you, you'll either have to leave the arena or kill him.