Me. Rev. Stat. tit. 18-C, § 5-201

A person becomes a guardian of a minor by parental appointment or upon appointment by the court. The guardianship status continues until terminated, without regard to the location of the guardian or the minor. This section does not apply to permanency guardians appointed in District Court child protective proceedings under Title 22, section 4038‑C. If a minor has a permanency guardian, the court may not appoint another guardian without leave of the District Court in which the child protective proceeding is pending.