Jane is a Lovestar monster, a pale pink hamster-like creature distinguished by a red star marking on its back. This species vocalizes with sounds resembling "love-love," leading to their name. Jane became Rokuna Hiiragi's companion following an encounter in the Water/Fire Realm. Rokuna's parting words, "Jā ne" (Japanese for "see you later"), were misinterpreted by the creature as receiving the name "Jāne."

Primarily residing on Rokuna's shoulder or in her room, Jane serves as a perceptive ally, frequently noticing critical details or dangers overlooked by the protagonists. While not a combatant, Jane aids the group through situational awareness and occasional assistance during challenges, such as playing a pivotal role in their escape from a Roc by utilizing unique capabilities.

Jane participates in episodic adventures, reflecting a bond of companionship with Rokuna. The character's presence occasionally facilitates humorous or lighthearted moments through reactions to the protagonists' predicaments or misinterpretations of events.