Setsuna Yuki

"'The Blazing Fires, Red Witch!'""-roll call""'Wielding The Powers Of The Ancient Niji Flames, Ancient Red Witch!'""-second roll call"Setsuna Yuki (優木せつ菜) is Red Witch and second-in-command to Pink Witch of the Nijimen. She wields the fire element.

Personality
Friendly and upbeat, Setsuna is smart and energetic. She is very oblivious to Kasumi's feelings for her. Despite her outgoing personality, she prefers to do things on her own but later learns how to work with a group. While she's mostly calm, she gets angry very easily and her fire power can cause her to overheat dangerously.

Background
Setsuna's father was the leader of Nijitopia's Fire Nijis. When the Darktopian Buccaneers invaded Nijitopia, her father was killed and her mother fleed into the human world.

Setsuna is the childhood friends with Kasami Nakasu/Yellow Witch. She barely spends time with her she spends her time studying, even on her days off. This caused her to be oblivious to Kasumi's feelings for her and do things on her own. Sometime later, she was given the Fire Niji Diamond.

In her second year at Nijigasaki Girls High School, Setsuna, and alongside Ayumu and Ai, encounters Pirate Swashbuckler. With the Fire Niji Diamond's power, Setsuna becomes Red Witch. She then summons Niji Fire Phoenix to form the Mahou Gattai Niji King.

She has a bit of rivalry with Dark Wizard Quartermaster Hades, especially through their accuracy skills. The quartermaster tests Red Witch;s anger, causing her to almost overheat. In Chapter 21, Setsuna nearly goes on a fiery rampage until KiNiji calmed her down. She defeats Space Quartermaster Hades but only leave a scar on his chest.

In Chapter 26, Red Witch becomes Ancient Red Witch alongside her team.

In Chapter 36, Setsuna and Kasumi have an argument, causing her to lose out her anger at her. This gets worse when Dark Wizard Quartermaster Hades made Red Witch reach her overheating limit, going on a full fiery rampage and nearly kills her whole team. She nearly kills Yellow Witch who runs to her and pushes them both from the cliff towards the sea. Stranded by the beach, Setsuna apologized to Kasumi for getting angry at her. Ancient Red Witch fights against Dark Wizard Quartermaster Hades one final time and finally defeats him, thanks to Ancient Yellow Witch lending her lightning powers.

In the final battle, Setsuna witnessed Kasumi die before her, who then tells her a dying 'I love you'. This caused Red Wutch to angrily attack Dark Warlock Cerberus but gets killed afterwards. In purgatory, she fights against Space Quartermaster Hades once more before resurrected back to life to aid Ayumu in defeating Dark Warlock Captain Erebus. After the battle, Setsuna becomes the Student Council President and also dating Kasumi.