Hellboy?
Liam
Some Australian Terms that might work for him:
Banger (sausage) Or Angry Banger lol
Blotto (very drunk)
Chokky (Chocolate)
Dinki-di (true australian)
Larrikin (a bloke who always enjoys himself, prankster)
Nipper (young surf life saver)
Ripper (great fantastic)
Yobbo (uncouth youth)
Hope that helps! He's adorable!!