Disclaimer: Please be aware that the following information is put together from a variety of sources, some more reliable than others. The following story is purely theoretical and should not be considered any more trustworthy than Racist Santa giving out candy in a rusty van.
Chin was born to Dade and an unknown mother long before the beginning of time in Realm 6.2. He grew to be a healthy child and mastered sports like chess and curling, without any signs of the cancer and evil that would later corrupt him. On his 21st birthday, Chin hosted a little birthday party and invited the almighty Based God. Dade noticed that Chin did not really have much of a wiener to speak of, while Lil B's was intergalactic, and argued with him about his manliness. Dade, disapointed by Chins incredibly tiny pecker, decided to sew Chins eyelids completely shut, as a form of punishment. Dade threw Chin out of his realm and told him to come back when he was a real man. Chin, travelling across many realms to find his hidden manliness, went by many different identitys to hide the shame of his extremely tiny penis.
Enraged and saddened, Chin roamed the realms looking for a way to impress his Dad again. He went to Men's College for Men where he met and was furiously bullied by Prometheus for being a total pusi. After graduating from his college, Chin could not find a single job to give him money to pay for his penis surgery. Furious, Chin became completely insane and brutally injured all those who bullied him during his youth. This left his former bullies like Prometheus almost dead, with Chin stealing many of Prometheus's chromosomes. This made Chin extremely rich with power, making his penis incredibly big. Prometheus would later gain his immense power back, due to winning the Chromosome Lottery.
Chin travelled to the realms he once grew up in, in hopes to meet his father once again. To Chins disappointment, Dade no longer lived in that realm and was believed to be dead. This made Chin very upset and angered.
Chin, now calling himself Chin-Chin, used his extensive power to travel across realms, inflicting fear among the people.
Chin-Chin is now known as The Dark Lord in Realm 6.2. He demands chromic sacrifices from the mortal inhabitants, both human and Lycra, and is known and feared by all.
Filthy Frank thought that Chin-Chin was dead for good, when, after a warning from Santa's Brother, he appeared in his apartment chanting "ochinchin ga daisuki nandayo". After the visit, Frank was forced to sacrifice some of the Chromosome Kid's chromosomes each day.
One day, Frank was carried away by Salamander Man's assflute and forgot to do the sacrifice. By the time he realised, Chromosome Kid had escaped. Enraged, Chin-Chin sucked Salamander Man with him to The Rock Paper Scissors Arena (after a short brawl with Lemon's Lemonjutsu) where he put a curse on him.
Frank traveled with Red Dick to the arena where he showed sacrifices performed by fans of the show to Chin-Chin, who was pleased enough. But when Senpai forgot his sacrifice again, Chin-Chin was ready to take Salamander Man to Jacksonville, Florida when he started playing his assflute. Touched, Chin-Chin let him go and has since almost stop bothering Franku's crew.
Months later, Joji returned to Frank's home and it pissed Chin-Chin off. He demanded monthly sacrifices from all who worshipped him. Even though his loyal minions had been sacrificing for him, Chin-Chin was still pissed and disappeared. This was around the time Creepy Dude showed up after a long absence and began hanging out with Frank and the gang, It was revealed in "PINK GUY COOKS TAKOYAKI AND RAPS" that Creepy Dude is actually Chin-Chin in disguise. He and Plastic Pinocchio disappeared.
Chin-Chin appeared once again during a hunt for Anime in Realm 69 Frank and Pookie, ambushing Frank after he had shot Pookie, and demanding more sacrifices in return for the henchman he lent Frank in WORST FILM EVER .
After Frank presented the Dark Lord with the sacrifices for 2015, Chin-Chin took Pink Guy from Frank, and banished Frank to Realm 0 (the location of the Rice Fields, motherfucker!), where he found Salamander Man. Although Frank would eventually make his way back to Pink Guy and Red Dick after many chromosomes, Chin-Chin has not been seen since banishing Frank.
~In the beginning, the gods sewed his eyelids shut in a desperate attempt to stunt chin-chin's rapid power growth. Obviously, this had no effect on him~
Ɔ̶H̶I̶N̶-̶Ɔ̶H̶I̶N̶ ̶S̶∀̶Ɔ̶ɹ̶I̶Ⅎ̶I̶Ɔ̶Ǝ̶ ̶ᄅ̶0̶Ɩ̶ϛ̶ ̶I̶S̶ ̶Ɔ̶O̶W̶I̶N̶פ̶
the translation of ochinchin ga daisuki nandayo is penis is the what I love.