Ashton Irwin is a spawn of Steve Irwin and Ashton Kutcher. He is not seen much because ashton kutcher and steve irwin rarely fuse. That's GOOD since everyone knows Luke Hemmings is EVUL!
An EVUL guy named Ashton Kutcher fused with Steve Irwin against his will. Ashton made him do stupid stuff all day until Titanaboa came, wacked Ashton Irwin causing him to split up, and ate Ashton Kutcher.
In 2011, Po found some of Ashton Kutcher's DNA in Titanaboa's barf. She got Dipsy to put some of the DNA into a specimen of Steve Irwin's, thus reincarnating the against will fusion known as ASHTON IRWIN.
Ashton later met Luke Hemmings in Germany, where he freed Luke from the German Prison. With Luke's other escaped inmate buddies, Calum Hood and Michael Clifford, they formed a band. It was 11:59 PM on September 22, the last day of summer, when they formed the band... 5 SECONDS OF SUMMER!
Humbah found their dead bodies and later, brought Ashton and Luke back to life, but they later began to worship Humbah as a god.