Here are some MHA-style names for a 15-year-old female character, categorized by different styles and potential character traits:

Hero Names:

• Graceful & Elegant: Seraphina Bloom, Luna Celeste, Aurora Dawn, Celestia Swift, Iris Whisperwind, Lumina Starfall

• Strong & Powerful: Valkyrie Blaze, Crimson Fury, Steelheart, Nightshade, Stormbringer, Iron Maiden

• Clever & Strategic: Enigma, Cipher, Oracle, Strategist, Mind Weaver, Shadow Strategist

• Nature-Inspired: Willow Whisper, Ivy Bloom, River Song, Moonbeam, Sunstone, Forest Nymph

• Quirky & Unique: Sparklebolt, Sugar Rush, Rainbow Dash, Pixel Pixie, Echo Bloom, Flutterby

Villain Names:

• Dark & Mysterious: Nightshade, Obsidian, Shadow Witch, Raven's Cry, Viper, Nightshade

• Cruel & Ruthless: Crimson Queen, Iron Talon, Venom, Malice, Serpent's Kiss, Death Blossom

• Cunning & Manipulative: Whisper, Illusionist, Puppet Master, Schemer, The Serpent, The Siren

• Fearsome & Terrifying: Banshee, Wraith, Nightmare, Reaper, Gorgon, Hellfire

Names with Japanese Influence (More fitting for the MHA aesthetic):

• Hero Names: Aoi Hana (Blue Flower), Sakura Kage (Cherry Blossom Shadow), Tsukiyo (Moonlight), Hinata (Sunshine), Kasumi (Mist), Yumeko (Dream Child)

• Villain Names: Kuroi Yami (Dark Darkness), Kagemusha (Shadow Warrior), Akai Oni (Red Demon), Shizuka (Silent), Yami (Darkness), Akuma (Devil)

Remember to consider the character's personality, quirk, and overall role in the story when making your final decision. You can also combine elements from different names to create something truly unique.