Fateseal is an old mechanic: (To fateseal N, look at the top N cards of an opponent's library, then put any number of them on the bottom of that player's library and the rest on top in any order)
Mtg print has bad support for flavor text, so it's formatted weird.
My boyfriend and I saw the art and immediately knew the vision we had in mind for it.
Earlier drafts of this:
• were more flexible, allowing you to put the cards in the graveyard. And while "fateseal 3 that opponent" just sounds weird, its brevity and clarity won out.
• instead of Shadow, there was the ability "Only creatures with vigilance can block this creature." More accurate in theme but too distracting from the main ability. We also played with not having this sort of ability at all.