Marya is, apparently, the aunt of the Scarlet Witch and Quicksilver. She had raised them, but until recently it was believed that Magda and Erik (Magneto) Lensherr where the twins' biological parents.

Marya Maximoff

Marya is, apparently, the aunt of the Scarlet Witch and Quicksilver. She had raised them, but until recently it was believed that Magda and Erik (Magneto) Lensherr where the twins' biological parents.

All data from the awesome folks at Marvel.