BT is a Wavemaster, considered by Helba Gate as a plotting and scheming character who forms friendships just to achieve a goal. She rarely ventures out to fight monsters, but she appears to be good with both offensive and defensive magic.
BT teams up with Crim to find the Key of the Twilight, a rumored powerful rare item. Her quest leads her to the upside down dungeon, where she discoveres the AI Harald.
A former model in real life, who now makes a career at a dispatch company in the Touhoku region. She lives alone in an apartment, and seems to have little interest in meeting with her old colleagues as it's shown in episode 17 Conflict when she tears the invitation letter of a class reunion into pieces. The envelope of that letter gives her given name as Machiko. Her family name is unknown.
She named her character after her favorite food, the B.L.T. (bacon, lettuce, and tomato) sandwich, minus the L for lettuce (a food she hates even though it doesn't have a particular taste or smell).