Larxene

Larxene (ラクシーヌ, Rakushīnu), also known as the "Savage Nymph" (非情の妖姫, Hijō no Yōki, lit. "Callous Vixen"), was first introduced in Kingdom Hearts: Chain of Memories where she conspired with Marluxia to overthrow Organization XIII. Larxene wields a set of knives called Foudre (エクレール, Ekurēru, lit. "Éclair"), the French word for lightning, and uses the power of electricity to fight. The character was first voiced by Rieko Katayama in Chain of Memories. Yuko Miyamura took over the role for the Japanese releases of Re:Chain of Memories and 358/2 Days, while Shanelle Workman provided her voice in the two titles' English releases.
She first meets Sora in Chain of Memories and helps manipulate his memories by causing him to remember Naminé's name. She then fights him and gives him new cards to access more areas of Castle Oblivion. After she discovers Axel's betrayal and sees that Marluxia's plans have fallen apart, she decides to reveal her and Marluxia's plans to Sora with the intention of killing him. However, Donald and Goofy arrive to assist Sora, and the three defeat Larxene, who fades into darkness. Larxene makes a minor appearance in 358/2 Days, reluctantly training Roxas before she leaves for Castle Oblivion.