It reads, Whenever Lord of the Void deals combat damage to a player, exile the top seven cards of that players library, then put a creature card from among them onto the battlefield under your control. While mill isnt likely to be your main strategy in a deck filled with Demons, the exiling is definitely nice
Multiples can also get discarded away easily with the plus ability
Giving additional prowess instances to your creatures is really good, and being able to make them unblockable more than makes up for this legendary rogues somewhat higher mana value
And there's a perfect Nazgul MTG commander just waiting for those players: Lord of the Nazgul's looking like one of the most popular commanders in an MTG set completely stacked with legendary creatures
What's interesting to me is that so far only 858 Choco decks featuring Keeper have been logged on EDHREC - it's not an obvious inclusion, and only 36% of players have decided to use it
I ended up taking reference photos of my mom