Matilda Grey-Summers

Matilda Rachel Storm Grey-Summers is the biological daughter of Scott Summers and Jean Grey. She is the younger sister of Nathan Grey-Summers.

When her mutant powers manifested, she started to get private tutoring from Professor Xavier for her telepathy, and her mother for her telekinesis.However, she didn't really need it as she had complete control over her powers from the second she had them. She is the only known class 6 mutant ever to exist.