It is implied that Rak climbs the Tower in search of 'something that transcends all things'. This would be something above wealth, glory, authority, and revenge.
SIU stated that "Wraithraiser" is actually the name of his race. The Wraithraiser species come from a place where there are only turtles and themselves to be found. Thus, they hunt and eat turtles; and regard everyone but themselves as turtles.
Rak loves bananas but has trouble peeling them. He also hates Quaetro for burning his bananas because they were yellow.
Rak likes eating meat, bananas, and childish food. He basically eats a lot.
Rak mini form was shown early in Best Challenge, right after the Crown Game, but it was later on Webtoon.
SIU has stated that Rak is a character that is very convenient to utilize, he doesn't use his head or hide feeling inside. So SIU doesn't need to think too much about his character. Of course, he is difficult to draw when he gets big.
His birthday is on July 7th.
(Answering Baam's question on the meaning of hunt) "To hunt is to make myself stronger. I push through powerful shinsu and I tear off and eat the skin of the strong!!!! That way I make their strength mine!! So I only fight strong enemies! I came here to find rivals that can make me stronger!! Like you and that weapon!! So! I will hunt you and your weapon! And become stronger!!"
(To Khun Aguero Agnis when he was moping) "A turtle that's even more useless than I thought. You said you sent a girl to sit by the king because she looked fit? Are you saying that as if you're boasting? If it was me, and there was a female that looked fitting to sit by the Alpha male, I'd snap that Alpha's neck and become the new Alpha. Then, wouldn't who I put beside me be my choice? IN MY EYES, THAT'S WHAT YOU'VE LOST! YOUR BANANA! YOU RETARD!!"
(To the passing Regulars) "You pathetic turtles, all hiding your heads inside your shells because of fear. That's why you're "nothing more than baby turtles". Ones who never freely put out their heads in fear of being eaten. I will go with him. I don't care what happens next. I never lose my prey. You can all just keep hiding in your shells and live a long life."
(To Baam while crying in tears, reunited) "You were alive...!! You were really alive....!! The black turtle is alive...!! I won't let you go... I won't forgive.. those who made you like this... I won't forgive them!!
(To Enemies in Workshop Battle) "If anyone tries to get in my way, I will crush them all!! I come! to meet the black turtle!!
(To Boro) "There is no need to be scared of the Ten Great Families or whatever. They are all just lousy turtle anyways. I know one guy from the Ten Great Families, but he is just blue and useless."
(Talking about Inieta to the No-named Regulars) "Shut up. I don't want you getting in my way. I'm glad he is the strongest because so am I. I will hunt him, so you guys can just go if you want to run away."
(To Baam) "Don't show me your weak side, turtle! You are my prey! I'm going to hunt you someday! You are not allowed to act like this around me! It kills my urge to hunt you!"
(To Baam) "I entered the Tower because I heard there is lots of though prey in the Tower. Just like they said, this place is crawling with prey stronger than me. But still, I don't want to stop climbing the Tower or hide! Only turtles who hide from enemies because they are scared would do something like that! Hunters charge into the enemies lair knowing they might lose their head. They could even get themselves killed. But that doesn't mean they are weaker than their prey. Prey thinks strength means staying alive. But a true hunter challenges those who are stronger than them without being afraid of dying. You are both the strongest prey and hunter that I ever set my sights on, turtle! No matter how strong your prey may seem, never give up and hide. Only the hunted do that! You have to be a hunter!"