Firstly, there is no return to the battlefield clause, so once you get something, its got. Secondly, you dont have to pass it until you use the upkeep trigger, which means at its worst, it is a 1WW [card]Revoke Existence[/card]
If he dies, the shadow elves and wood elves will almost certainly split once more and resume their ancient war
Youll want to back it up with a hefty suite of protection spells, since optimized Arabella decks can end the game in just a couple of attacks
Legality depends on the tournament format -- Power Fist can be legal in some formats and banned or restricted in others
In Crusade's case, it was the Christian crosses that were the source of the controversy
But I recommend the Professors video on Cube to get started: MTG Arena MTG Arena had the cards for a short little event back in December 2019