AzoriusLegendary Artifact Creature — Robot DogRex, Cyber-Hound
Mana value3Rank#9,084
The Commander
Whenever Rex deals combat damage to a player, they mill two cards and you get 
(two energy counters).
Pay : Choose target creature card in a graveyard. Exile it with a brain counter on it. Activate only as a sorcery.
Rex has all activated abilities of all cards in exile with brain counters on them.
Guide
Gameplan
Rex is a value/toolbox commander that mills players on combat damage and banks energy, then 'cages' creature cards from any graveyard under brain counters to inherit their activated abilities. You connect with Rex for commander damage and mill, exile juicy creatures (yours or opponents'), and turn Rex into a Swiss-army robot dog with mana abilities, removal abilities, and engine pieces. Late game you win with commander damage, mill, or an assembled ability combo.
Strengths
- Snowballs hard once Rex connects: each hit mills two and pays for a future cage activation.
- Can steal value from opponents' graveyards since you mill them yourself, denying recursion while gaining their abilities.
- Permanent ability accumulation makes Rex resilient to a single removal spell on a caged creature (the brain counter exile sticks).
- Lives in UW, the best colors for protection, evasion, and counterspells to keep your engine running.
Weaknesses
- Three-mana commander with no built-in evasion or protection, so Rex gets chump-blocked or removed before connecting.
- Engine relies on combat connection AND graveyard fuel—two failure points an opponent can attack.
- Many strong activated abilities require resources Rex lacks (its own +1/+1 counters, the creature's own body to sacrifice), limiting what's actually usable.
- Slow to assemble compared to dedicated combo decks; vulnerable to graveyard hate and exile-based removal of Rex itself.
Key Cards
- Sword of Body and Mind — Grants evasion and protection while milling ten on hit, fueling both the brain-counter targets and your own win-by-mill plan.
- Rogue's Passage — Guarantees Rex connects for damage, energy, and mill against decks full of blockers.
- Whispersilk Cloak — Makes Rex unblockable and shroud, protecting your accumulating-ability engine while ensuring combat triggers.
- Mesmeric Orb — Cheap, repeatable self-mill that loads your graveyard with creatures to cage.
- Walking Ballista — A premier caged ability target in any color identity; pair with proliferate to feed pings, though Rex needs counters to use it.
- Aetherworks Marvel — Turns your stockpiled energy into card advantage and a backup engine alongside Rex's energy generation.
- Teferi's Protection — Saves Rex and your locked-in caged abilities from a board wipe or targeted removal.
Upgrade Path
Add fast mana and evasion enablers (Sol Ring, mana rocks, Rogue's Passage, more swords) so Rex connects on turn three or four and the engine comes online early. Tighten the cage targets to creatures whose abilities Rex can actually use on its own and identify a true two-card ability loop for a deterministic kill, then back it with tutors like Open the Armory and Whir of Invention. Finally, layer in protection (Heroic Intervention, Teferi's Protection) and graveyard insurance so a single piece of removal or graveyard hate doesn't collapse the plan.
Core Cards
The most-played cards for this commander, built from aggregated deck data (the Mythic Graph). Build public decks to seed it.
Win Conditions
- ▸Commander damage from an evasive, equipped Rex (21 over a few swings).
- ▸Milling opponents out via repeated combat triggers plus self/opponent-mill pieces.
- ▸Assembling an activated-ability combo through caged creatures (e.g., mana + payoff loops).
- ▸Inevitability through stolen value—out-resourcing the table with caged engines and card draw.
Archetypes
- Toolbox/Ability Theft — Caging creatures with brain counters lets Rex assemble any toolbox of activated abilities from graveyards like a budget Mairsil.
- Mill — Combat triggers mill opponents two at a time, and equipment like Sword of Body and Mind can push mill into a primary win path.
- Voltron — UW protection and equipment turn Rex into an evasive, hard-to-kill commander-damage threat.
- Control — UW counters and board wipes stall the game while Rex's engine grinds out incremental advantage.
Combos
- Rex, Cyber-Hound + Pili-Pala + Palladium Myr
→ Infinite colored mana, Infinite colorless mana
- Rex, Cyber-Hound + Pili-Pala + Vhal, Candlekeep Researcher
→ Infinite colored mana, Infinite colorless mana that can't be spent to cast spells from your hand
- Rex, Cyber-Hound + Pili-Pala + Kozilek's Channeler
→ Infinite colored mana, Infinite colorless mana
- Rex, Cyber-Hound + Trench Behemoth + Walking Atlas
→ Infinite landfall triggers, Infinite mana lands you control that enter the battlefield untapped can produce
- Rex, Cyber-Hound + Trench Behemoth + PuPu UFO
→ Infinite landfall triggers, Infinite mana lands you control that enter the battlefield untapped can produce
Combos via Commander Spellbook.
Related Commanders
Same color identity (UW), by popularity.
