6 mana over two turns to cast a spell from your graveyard, and hopefully nobody kills it before you can pull it off
your opponent has to wait another turn before they wrath, or you make a bunch of tokens right after
For those not in the know, these two siblings have been integral to countless moments in Magics story, and are some of the most mythic of characters in the story, albeit not quite as popular as the likes of Nicol Bolas
The ability to grow and also draw cards whenever a creature enters keeps the green deck going
Undercover Butler meanwhile speaks to the kinds of decks in Dimir that really want to push damage through, either to kill a player, or pull off a nasty damage trigger
It also triggers cards that care about permanents entering the battlefield (if the spell resolves), and so on