After the events of Little Big Planet 3, Sackboy found a portal of Skylands. He went inside it, and found Skylands, and Portal Master Claus. He wants to help him so he went to Jr. Skylanders Club, and found three graduated Skylanders he wanted. One is the Almost Mecha Lion. Another is Arachnus, and also a Charizard named Firey. Soon with Trap Team in Skylands and new villains Sackboy grabbed 3 traps and try to trap villains. First Fassad was terrorizing Willow Woods city, so Sackboy used his tech trap to trap him. Then Chef Pepper Jacks brother Cook Jalapeno planned to turn Dragon Island into Pizza, so Sackboy used his fire trap to capture him. Then a strange flying squirrel named Nutjob stole the golden nut, so Sackboy used his air trap to catch him.
Sackboy is an actual character in Little Big Planet series.
His Skylanders are based off of Portal Master Claus' Skylanders. Almost Mecha Lion and Ultimate Chimera are both Mother 3 Skylanders. Aranchnus and Ridley are both Metroid Skylanders, and Firey and Drago are both Pokémon Skylanders.
His Skylanders are all the same Element as their friends, except for Firey, who is a dual type.