Kaldur killed his first eel when he was nine. It followed him home, nipping at his heels until Kaldur lost his temper and struck back. The eel's skull smashed into the rock. That hadn't been enough to kill it, but it was enough to make it writhe in an endless scream of pain.
Kaldur reached with both hands and pressed anywhere to break the bones enough to kill it. There was crack after crack until finally the eel stopped moving and Kaldur was left filtering the eel's blood through his filaments. It seemed really frustratingly messy.
He was sure there had to be a cleaner way.
He started swimming on the border of shark territories when he was nine. He wanted to see if there was a cleaner easier way. He knew that killing people was wrong, but there were no laws against defending yourself from attacks. It takes a dozen tiger sharks before he gets it right. Before he learns how to make it clean and quick, and most importantly efficient. That's when he stopped swimming near shark infested water.
As Kaldur aged, he grew ashamed of this childhood hobby he had developed. His work with his Queen and King made him more aware of the preciousness of life. He had a duty as an Atlantean to protect and defend. He enjoyed it. He was good at it even.
A part of him wondered if he's so good at being a Warrior because of his childhood hobby. His fighting is efficient. He won't waste water if he can help it, nor will he throw another blow when one hit will suffice. He doesn't have a taste for killing and he finds the thought of killing another person, villain or civilian, absolutely abhorrent.
Still he wondered if a human can be cut down with the same clean efficiency. Black Manta knew how to do it to an Atlantean. Kaldur found the murders to be vile, but a part of him wondered if it would be as effortless as sharks.