Ward and....? (Terminology question)

All right, if young Philip is my ward (in a legal sense), how am I refered to by him? I am his…? And does it vary if either his gender or my gender is different?

Guardian?

Guardian is the correct term. The legal definition of ward is “A minor or incompetent person placed under the care or protection of a guardian or court.” Both terms are gender-neutral.

Are you sure it’s not Ward and Batman?