Desmond Miles gets +1/+0 for each other Assassin you control and each Assassin card in your graveyard.
Whenever Desmond Miles deals combat damage to a player, surveil X, where X is the amount of damage it dealt to that player.
Desmond Miles is a mono-black Assassin-tribal voltron-aggro commander who scales his power with every Assassin you control or that dies, then connects with menace to surveil into more gas. You flood the board with cheap Assassins, swing in with an ever-growing Desmond, and use surveil to fuel graveyard recursion while grinding opponents down one at a time.
Cheap two-mana commander that comes online fast and threatens early damage.
Menace plus self-scaling power makes him hard to block and a real commander-damage clock.
Surveil engine smooths draws and feeds graveyard/reanimator strategies.
Mono-black gives access to the best tutors, removal, and recursion in the format.
Assassins that die still pump him, so trading creatures is rarely a loss.
Relies on connecting in combat, so it folds to fogs, removal, and chump-blocking.
Single-target removal on the commander resets your damage clock and tempo.
Thin Assassin tribal pool means many slots are generic black goodstuff.
Mono-color gives no card advantage outside black's life-loss draw.
Goes wide but is vulnerable to board wipes that erase your power bonus.