"Never forget your color....you alone now kee-keep us here. Purple for life...."
-Puck's final words to his friend Purple Mutineer.
Puck was just a regular gang member until the Tuba Gang Leader killed his leader. Then in The Alliance once they heard that they'll be facing Lil Jeffy, the two came with a idea to betray the Tuba Gang Leader and join Lil_Jeffy instead. They told other members of their plan and it sprung to action. In The Fall, Puck and the other Mutineers killed off members of The Strangers causing The Strangers Leader and the remaining Purple Republic to attack Lil_Jeffy, his allies, and the Mutineers. Puck managed to survive but he had to jump off the Puffle Hotel and into the Mall. This is where he met his fate.
Puck didn't expose any bones unlike the other two but he broke many bones and tumbled down the escalator. He managed to survive for a short amount of time. During this, the Purple Mutineer apologized and said that it was his fault. Puck however said that he would rather die like this on his terms than serve a asshole like the Tuba Gang Leader. He seemed glad that at least his friend would survive and continue on. Puck then told Purple Mutineer to never forget his color and that he alone now holds the Mutineers of the Purple Republic together. He says a catchphrase of the Purple Republic before dying. This seemed to have upset the Purple Mutineer and gave him a grudge against the Tuba Gang Leader.
In The Plan, Lil_Jeffy can see Puck's body being dragged away by what seems to be nothing. During Purple Mutineer's talk about The Cannibal, the puffles from Floppy Green Penguin were taking the bones and insides out of Puck. Eventually, Puck's body became the Floppy Purple Penguin and his story alive ends here.
Puck looks exactly like his gang allies, a purple penguin with a mining hat.
Purple Mutineer was Puck's closest ally and likely friend. They both planned the betrayal of the Tuba Gang Leader, although this caused his death. Puck's death caused Purple Mutineer to gain a huge hatred towards the Tuba Gang Leader.
The Tuba Gang Leader killed his leader and took over to which Puck says it isn't right. Another reason for hating the Tuba Gang Leader is likely because of how blind he was to kill Lil_Jeffy despite that he is aware of the penguins dying. Puck would rather die than work for him.
They didn't interact at all, but Puck considered joining Lil_Jeffy a sweet revenge on the Tuba Gang Leader for taking over the Purple Republic.
Puck despite being a mutineer seems very royal to the Purple Republic. Even saying that the Purple Mutineer holds it together. He values it so much, it was his last advice to his closest friend. To never forget his color.