Bellatrix is Weed and Koyuki's only daughter, sister of Sirius, Orion and Rigel. Although she is sister of the protagonists, she does have a very little role in GDW:O.

The only female of the litter, she is very whiny and timid and has to be rescued by her brother Sirius from her other two brothers, who keep bullying her. She was named by Daisuke and made a brief appereance at the ending of GDW, as a newborn puppy.

In GDW:O, she is separated from her brother Orion by a volcanic disaster, followed by earthquakes that happened in Ohu. She found a shelter with Sirius, Rigel and Sasuke. She got lost after the catastrophic events but was saved by two of Akame's grandchildren: Shirozaru, Muu and Rara. She does not have any big role in the story and lives as a pet dog in safety.

in TLW, Bellatrix is shown together with his mother and brothers. After knowing from Akame that Moonsoon has taken over Ohu, she asked his brothers to go with them but Orion tells her to stay with Akame and Koyuki because she would be a burden with them.