Sen Triplets
The hard part of theft-as-mechanic is that most of it expires too fast to matter: steal a card, cast it this turn, and the window slams shut before you have built anything. The three sisters answer that by relocating the theft to your upkeep, where it compounds. Every turn one opponent is locked out of casting spells and activating abilities entirely, plays open-handed, and surrenders their cards to you for the turn. That is two effects fused: a Mindslaver-flavored lockdown on the chosen player and a recurring raid on their hand. The trick is in the timing. Because the choice happens at your upkeep before you draw, you survey a revealed hand and spend your own turn emptying it of whatever helps you, while that opponent sits frozen and cannot respond, cannot interrupt, cannot even crack a fetchland. Holding three colors of pips on a 3/3 is the cost of stapling that much board-state control to a single creature; the body is fragile enough that the soft-lock only holds while the sisters survive to trigger it again. What makes the design hum is that it does not pick a victim once and grind them out: it can rotate targets, defanging the most threatening opponent each turn while leaching their best card. It is a control engine wearing the clothes of a casual three-color commander, which is exactly why it has outlived the table it was built for.
