The Mother of Matthew Murdock (Daredevil). She left when he was very young to become a nun. Matt found his mother in the Born Again story arc (in Daredevil #229). They reunited on different occasions. In the storyline Guardian Devil, Daredevil, plunging off a roof after being drugged by Mysterio, saved himself and ended up in front of the Church were Sister Maggie was. She took care of him while he was resting. Later they hugged.
Major Story Arcs
Lone Stranger: Cremains
For more information see: Lone Stranger
Daredevil comes to see Sister Maggie while she is discussing God's love and forgiveness with a group of children. He over hears her say God forgives everyone, even the devil. He then asks where the priest is and goes into the confessional. After emerging, he leaves the church without so much of a nod to the sister.