Prior to Calabash
Sometime after MK defeated the Demon Bull King, Jin and Yin heard about MK and knew that he would be a perfect adversary to them. So Jin and Yin made MK delivered noodles to their hideout so they can trap him in the Calabash.
After making the Mei's Calabash counterpart fall in love with MK, Jin attempts to fix his mistake but was stopped by Yin, who thinks that Jin is just going to tell MK that everything's perfect again. Moments later, Jin uses the Calabash again to fix his mistake.
When MK found the Golden Staff in the Calabash, Jin and Yin used the Calabash counterparts of MK's Team, the Monkey King, and Mo to convince MK not to take the staff. However, after Jin realized that cats can't talk, he and Yin used the counterparts to prevent MK from taking the staff but failed.
Once MK broke free from the Calabash, Jin and Yin told him about themselves and how he got trapped in the Calabash. Although, when MK attempt to fight them, Jin and Yin escaped.
After MK joined the Great Wall Race, Jin and Yin remind him that they are in the race as well. However, once the Demon Bull King and Princess Iron Fan joined, Yin and Jin quitted the race and became the announcers.
During the race, Jin and Yin commented on the racers and what they did until MK and Mei won the Great Wall Race.
Like his brother, Jin likes to frighten other people who are unaware of him so he can make them think as a major threat, as he was scared of MK at first when he broke free from the Calabash but acted intimidating after MK questioned who he was.
In "The Great Wall Race", it was revealed that Jin likes to take control of competitions so he and his brother can make things difficult for the participants rather than win, as the Gold and Silver Horn Demons wanted to compete in the Great Wall Race so they can win at first but decided to become the announcers and change the course when the Demon Bull King and Princess Iron Fan joined the race.
Jin looks like his brother except he is an orange-skinned demon with orange horns and golden hair.
Jin wears a black armor collar, cross straps with a gold emblem, and black pants.
The Calabash was an ancient relic that allowed the user to imprison the Calabash's victims in a different universe. It was used by Jin and Yin to trap MK and imprison him there.
Via the Calabash
In Journey to the West