Garna

Garna was an assassin who was hired to poison Princess Primula while acting as her attendant, but when Argent came on the scene his attempts were foiled and he was found out. He was imprisoned in the dungeon until Primula realized she needed his expertise to help her and Lorca discover a cure to the illness that was plaguing Navara. He’s later made a chef at the castle and becomes a valuable ally to Primula. Source: manga