"Special trait: Water Works"
After Astaroth had made his outrageous claim that Ian would not be able to defeat him, Astaroth activated his own special trait which was directly connected to his own weapon. Using his special trait, not only was Astaroth able to turn his trident into water itself but also managed to turn his own body into water before sliding down on the ground so he could move away from the area which the chains that Ian had cast so keep Astaroth in place.
"You see, there was never a chance of you actually defeating me. Just you alone turning around after you managed to put me inside silly trap shows how inexperienced you truly are in the art of combat," Astaroth explained to Ian.
"Oh really? So what do you plan to do with me now? You must want to have a battle where you show off some of your moves before killing me, after all I'm your enemy so it would only make sense, right?" Ian asked while keeping a sarcastic tone.