"Wdym you can't? The cell is wide open, and nothing should be stopping you...so what's wrong?"
"I....every prophesy has-a catalyst. Something that pulls me to it-literally. And in this case...it's you."
Siren saw a glowing orb at the center of Kappa's chest, a thread of energy flowing outward from it and connecting him to Siren.
"...If I try to escape...I-I'll just end up getting pulled back-"
It faded away on it's own, though still present-
"It's more like I'm connected to you. You could go wherever you want-I'd just get pulled along with you. I mean...I-I've tried to escape prophesies before...but usually I can't swim very far from the catalyst before I get pulled back...and it's because you're....y-y'know....meant to kill me....?"
He gestured at the abandoned spear
He kinda smiled and swam into the cell, now in front of him
"Of course! I mean i have nothing better to do....also i wanna help you..."
While most of what he said was true, the part of him having nothing to do was a lie...he knew he had to hep the kingdom yet he knew he wouldn't be able to kill him...