Here is a easy method to kill Gernichora in Thronebreaker The Witcher Tales game.
Useful cards: Meve: Ornamental Sword, Strays Infiltrator, Decoy, Reinforcements, Command: March, and other cards that doesn’t add any power to your side.
The strategy is quite simple, it involves a Strays Infiltrator to boost itself with Gernichora‘s HP and letting it be the only card in your battlefied. After that, use Meve: Ornamental Sword to kill Gernichora.
While waiting to the leeches move to the ranged row, try using a card that doesn’t add any forces to your battlefield. e.g. , Decoy, Reinforcements or Command: March!.
When Strays Infiltrator is the only card in your rows and Gernichora is not immune, use
Meve: Ornamental Sword so you can duel Strays Infiltrator with Gernichora.