You can only use activated abilities and keywords on your turn not your opponents unless specifically stated
History suggests that you'll have to act quickly to get these in your cart
Notably, And Along Came Zeus can quickly wipe out Beast Relentless, stopping its potential infinite loop combo in its track
Similarly, why include a bunch of characters that bounce characters back to the hand when banished and a bunch of cards that heal characters
Here is my attempt to group them by era to help folks understand the evolution of the franchise: FINAL FANTASY through FINAL FANTASY V : Rooted in fantasy, linear narrative, fixed party
Oh, and he has a tail, but really, it's the fashion choices we notice over anything else