It's a scary Abzan card that can be built as an attrition-style deck, or with flat-out Necrobloom combos in mind
These cards allow a player to recover cards from the discard pile, draw them, or even look through their decks for specific cards that the Trainer Card allows
By listening to adventurers recount their exploits and weaving them into verse, he brings forth high-difficulty versions of raids and trials (yes, really), so he should somehow create a permanent that represents a powerful and scary version of an enemy
It is also the third and the last Meld card in the new set, which combines with The Mightstone and Weakstone legendary artifact, and creates Urza, Planeswalker
While you have a handful of creatures that won't be affected by Serpent of Yawning Depths, it's a key to being able to close the game with your tokens as an army of unblockable 3/3s will help get your opponents' life totals lower