Seeing Karlach slam into play feels like flipping on a red switch — everything wants to go fast and brutal. I build toward that instinct: give her haste, ways to double damage, and redundancy so a single removal spell doesn’t shut down the whole plan.
For quick, punchy synergy I love pairing Karlach with equipment and one-shot finishers. 'Embercleave' is obvious — it turns any successful attack into a lethal swing, especially if Karlach already threatens damage or triggers on attack. Creature-wise, cards that either replace themselves or survive combat trades (think something that trades up like 'Bonecrusher
Giant') keep the pressure while filling the
graveyard for value. 'Anax, Hardened in the Forge' is wonderful if your Karlach deck creates or benefits from small bodies or death triggers, because Anax grows and taxes opposing removal. 'Chandra, Torch of Defiance' or similar red planeswalkers buy time and turn awkward draws into gas.
Sideboard and tempo choices matter: cheap interaction to protect your plan, and card-draw like 'Light Up the Stage' to find your combo pieces. In practice I lean into the aggressive gameplan — make them answer one huge threat or die — and that’s exactly the kind of feel Karlach gives me at my table.