The Most BROKEN New Strategy in Merge Tactics S9: Full Undead Carry Guide
Full Undead (6/6) is the highest-ceiling comp in Merge Tactics Season 9. Why the stacking +HP/damage stat carries between rounds breaks the game, how to flex when you can't roll Skeleton Dragons, and why Monk from Quest Orbs is the lock-in plan B.
Credit: ReTaik
Why Full Undead is the strongest comp in S9
The whole point of Full Undead in Season 9 is that the Undead trait scales across rounds, not just inside one fight. Every ally KO triggers a permanent +1% / +2% / +6% HP and damage buff to every Undead on your board, and that buff carries over round to round. By the mid-late game your Undead are wearing a stat boost bigger than what any other trait can hand out in a single fight.
The Noble trait is the honourable mention for armor and damage, but the per-round snowball on Undead is what makes it the best comp on the board.
"Even after a round ends, you're going to keep the same stat boost. So you can easily just snowball these stat boosts and just carry them on to the next round.": ReTaik
The ideal 6/6 Undead board
To hit a full 6/6 Undead you need every Undead troop active in S9 on the field together:
| Troop | Cost | Notes |
|---|---|---|
| Bomber | 2 | The cheap 2-cost Undead opener |
| Giant Skeleton | 3 | Frontline + bomb on defeat |
| Royal Ghost | 3 | Cycle-friendly invisibility |
| Skeleton Dragons | 4 | The hardest Undead to roll: gates 6/6 |
| Witch | 4 | Skeleton summons feed Undead KO triggers |
| Skeleton King | 5 | The captain |
The bottleneck is Skeleton Dragons. If you don't open one (Quest 1 Orb or shop) you usually can't lock in a true 6/6 Undead. The realistic plan is to settle on 4/6 Undead and flex the last two slots elsewhere.
Plan B: what to do if Skeleton Dragons doesn't show up
This is the practical scenario most of the time. Statistically you won't hit Skeleton Dragons every game, so you flex:
- Stay on 4/6 Undead. That already gives you +2% stacking per KO, which still snowballs hard.
- Roll the Quest 2 / Quest 3 Orbs with a Boss troop in mind. Both T2 and T3 Orbs drop a 2★ / 3★ Boss (P.E.K.K.A., Mini P.E.K.K.A, Monk, Mega Knight).
- If Monk shows up, lock in around Monk. He is the strongest single troop in S9 right now, and the Shield plus heal cycle means the back two slots just become Monk plus one flex.
- Mini P.E.K.K.A from the Orb is the wildcard. Pancake levels up a random ally every few hits, and because Boss troops only appear in your shop once you've unlocked the Orb, opponents physically can't block your Boss roll.
- The last two flex slots can be a 3★ Prince for Noble bonus, Archer Queen, Golden Knight or anything that activates a secondary trait.
"Like, the probability of somebody actually having a Mini P.E.K.K.A: two people having the same Boss troop is really low. So it's pretty hard. It's not possible for someone to block.": ReTaik
Ruler: Spirit Empress (Fusion Foresight)
Spirit Empress is the recommended Ruler because her quest is Merge 3 / 15 / 50 troops in one game, which is exactly what an Undead board does when it spam-cycles low-cost troops to stack the trait. Spirit Empress consistently delivers you to Quest 3, where the Boss-troop and trait-instrument rolls happen.
- Quest 1 Orb roll target: Skeleton Dragons (the 6/6 lock) or Equipment (Assassin Blade is the strongest hit-then-jump item on Skeleton King).
- Quest 2 Orb roll target: a 2★ Boss troop (Monk or Mini P.E.K.K.A).
- Quest 3 Orb roll target: 3★ Boss troop or Undead Drum. The Forest, Noble and Goblin trait instruments are nearly useless on this comp; you want the Boss star-up or the Undead Drum to push 6/6.
Reward priority across the Quest Orb tiers
A small ranking from the video to memorise:
- Quest 1 Orb: Troop > Elixir > Equipment. Skeleton Dragons is the dream.
- Quest 2 Orb: 2★ Boss troop > Combat-Start Equipment > Elixir.
- Quest 3 Orb: 3★ Boss troop > Trait Instrument (only useful if it pushes a trait one tier up) > Elixir.
General rule: with Spirit Empress the item slot is the worst roll in almost every tier. Boss troops carry the game.
Don't sell your Undead
The Undead stat boost is bound to the trait being active on the board, not to a specific card on the bench. Selling Undead troops keeps the trait alive on your board, so cycling 2-cost Bomber or Royal Ghost copies is fine. What you should NOT do is drop your active board from 4 to 3 Undeads, because that loses you the tier-2 stacking buff entirely.
If you're under elixir pressure and need to sell, sell the lowest-star duplicates and let the active 4 Undead stay on the board.
Modifier matchups
A few Season 9 modifiers worth flagging for this comp:
- Echo Bench: every round, a 1★ copy of your right-most bench troop. Park an Undead there for a free cycle every round.
- Last Survivor / Battle Royale: Undead works fine with the poison floor because the KO buff is board-wide and your Skeleton spawns from Witch keep feeding KOs.
- Goblin's Treasure: extra Orb if you can break the enemy's. Treat it as +50% chance to hit Quest 3 thresholds early.
Closing: why this is the strongest comp right now
The TL;DR from ReTaik's run:
- 4/6 Undead is reliable, 6/6 is the Skeleton-Dragons-dependent ceiling.
- Boss troops from Quest 2/3 Orbs make the last two slots literally unblockable.
- The Undead between-rounds stat carry is what no other trait offers. It scales with time, not with merges.
- Monk plus Undead board is the most consistent finisher when Skeleton Dragons doesn't show.
Check the new trait bonuses, browse the Boss troop pool, or jump to the Quest Orbs guide to plan your next ladder push.