Descend 8 — The Ancient One can't attack or block unless there are eight or more permanent cards in your graveyard.
: Draw a card, then discard a card. When you discard a card this way, target player mills cards equal to its mana value.
The Ancient One is a 2-mana 8/8 (in practice a big beater) that comes online once you've filled your graveyard with eight permanents, while doubling as a self-mill engine and a mill wincon via its loot ability. You spend the early game dumping permanents into your yard with self-mill and sacrifice effects, then either swing for big chunks of commander damage or mill an opponent out with repeated activations of high-mana-value discards.
Cheap commander that turns into a sizable evasive-less but hard-hitting body once Descend 8 is met
Built-in card filtering and graveyard fueling that synergizes with reanimation and dredge themes
Can mill opponents out as an alternate win condition, especially discarding expensive cards
Dimir gives access to the best card draw, removal, and recursion in the format
No evasion and can't block until Descend 8 is active, leaving you defenseless early
Mill as a win path is slow and weak in a multiplayer pod without payoff support