I'm creating a character for a new campaign based on Svetlana Chmakova's Nightschool manga. The charcter is a Weirn, sort of a witch, who's familiar, an astral, is an extention of the character's self. The astral is a seperate entity that is always near the character and can go invisible, twist 1/2" steel railings into decrotive patterns, punch through brick walls and change into wings for the character to fly. The character I'm building will have a much less powerful astral than the source material with the slips through cracks form of desolidification, invisibility and aid intelligence of the main character only.
To represent this I'm considering building the astral as a seperate character and charging the main character for this 2nd character as duplication. Both the characters have a dependance with incompetency to each other.
Is there a better way to represent this dual character in 6E rules?