Medomai the Ageless + Idris, Soul of the TARDIS + Karn's Bastion + Encroaching Mycosynth
4-card combo · URW
Verdict
Yes — this 4-card loop chains infinite extra turns through Idris's vanishing upkeep and Karn's Bastion refilling its time counters each cycle.
- Cards required
- 4
- Cheapest stack total
- $4.40
- Color identity
- URW
- Popularity
- 0 decks
- Format
- Commander
Medomai the Ageless generates the first extra turn by connecting in combat; Idris, Soul of the TARDIS then enters to exile Medomai and deal its own damage, triggering another extra turn. On each subsequent upkeep, Karn's Bastion spends 4 mana to replace the time counter Idris's vanishing removes, keeping Idris on the battlefield indefinitely — Encroaching Mycosynth is the glue that makes Idris a legal target for Karn's Bastion by making it an artifact. The prerequisite of having an unblocked path is the real work; once combat damage lands, the loop is airtight.
Recipe
How it works
01
Prerequisites
An opponent cannot block creatures you control.
02
Steps
- Deal combat damage to an opponent using Medomai the Ageless.
- Medomai the Ageless triggers, causing you to take an extra turn after this one.
- Cast Idris by paying
. - When Idris enters the battlefield, it triggers, exiling Medomai the Ageless until Idris leaves the battlefield.
- Move to your extra turn.
- At the beginning of your upkeep, Idris's vanishing ability triggers, removing a time counter from it.
- Activate Karn's Bastion's second ability by paying
and tapping it, putting a time counter on Idris. - Deal combat damage to an opponent using Idris.
- Idris triggers, causing you to take an extra turn after this one.
- Repeat from step 5.
03
Result
Infinite turns; Lock
Variations
Cheaper, tighter, alternate lines
Karn's Bastion can be swapped for any effect that places a time counter on a permanent, such as Clockspinning or Jhoira's Timebug, though those require repeatable access. The combo needs a reliable evasion enabler — Reconnaissance, Tetsuko Umezawa, Fugitive, or mass-evasion like Archetype of Imagination — to satisfy the unblockable prerequisite every loop; without one, the chain stalls the moment an opponent deploys a blocker.
Related
Other combos sharing these cards
Tekuthal, Inquiry Dominus + Magistrate's Scepter + Lithoform Engine + Karn's Bastion
Infinite turns; Lock
Verified on Commander Spellbook · Combo ID idris-soul-of-the-tardis-karns-bastion-medomai-the-ageless-3
Updated . Data from Commander Spellbook, Scryfall, and EDHREC.