Everyone considers their powers terrifying, cursed, and ugly. But Kija, who probably has the most visibly ugly and monstrous power, takes the most pride in his abilities and is like "haters gonna hate" when people call him a monster or a puppet.
Even if his predecessor did something horrible to him as a baby, he takes all things into consideration for why that happened and forgives him, and he's had this insight from the time he was just a young boy. He took something horrific and turned it into his strength. So even when Jae-Ha says how emotionally hurt he must be from it, he can say with pride that it is not the case at all. Kija is everything Jae-ha dislikes incarnate, and the fact he came to respect him after that says a lot.
Though after considering everything, I wonder how his character would have been if his upbringing had not been so stable and loving, or if he were more vain (ha ha). As far as we know, the other three had horrible lives, with the only people who ever cared an ounce for them disappearing at young ages (still know nothing about Zeno, so take this as half-true for now). They have valid reasons to feel spiteful of their powers or the legend, and Kija can't really tell them they're wrong because their experiences are different from his.
Though this is the reason I think he wants nothing more than to go to each individual village and bash some heads, if not just stand there menacingly with his claw extended to scare them all. Seriously, I can imagine that.