Once you have everything set up in terms of an account, you'll want to create a new submission using the Online Form for trading cards
Be wary of your surroundings though, the environment around the Arena has the potential to strengthen your Beasties, or even weaken your Spells
Probably in one of the older core sets)
The rapidly accumulating card advantage alongside dealing extra damage each time a ninja you control connects in combat can quickly snowball games, especially when a 1-drop gets through unchecked on turn 2
The removal trigger comes upon attacking, so if things go your way then you blow up their best blocker and suddenly Armix puts your opponents into a pickle
If you notice any missing cards, mistakes, or low quality images let me know and I'll update them eventually