Shadowheart, Dark Juusticiar Shadowheart, Dark Justiciar gets everything that the Half-Elf Cleric is all about in terms of flavor, from the Black alignment to the shoutout to Shar in the lore text
Polliwallop is our removal spell, and it's a good one, dealing damage equal to twice the power of a target creature we control to one of our opponent's creatures, typically for just one mana (thanks to its cost reduction) at instant speed
Not a bad deal
Keep them sealed if your main goal is collecting sealed products, but remember that condition, set popularity, and scarcity matter
If a ton of cards are going to be hitting the graveyard anyway, we might as well profit
Honestly, the only real problem youd have is figuring out how to get no maximum hand size when limited to black-green