It's ETB is to recur a dork to the battlefield with menace, deathtouch and haste and then it gets exiled EOT from any graveyard that cost for or fewer
I don't know that I really like Serra as the flying lord
I would feel almost entitled to run this in mono white, given the color can still sometimes feel like its punching up, but what makes white decks able to utilize this well is the lifegain that white can do very well
The key limitation to keep in mind is that the enchantment sacrifices itself at the beginning of the end step, so youre working on a clock
Mystic Enforcer could easily be slipped into more "normal" builds than its cheaper brethren for several reasons
3-mana: +: One 0/1 (Nissa, Voice of Zendikar), one 1/1 with defender (Daretti, Ingenious Iconoclast), one 1/1 with upside (Grist, the Hunger Tide, Modern Horizons) 0: Two 1/1s you sacrifice at end of turn (Chandra, acolyte of flame, not actually protective tokens) -1: One 1/1 with flying (Dovin, Grand Arbiter