Lucille is Marv's parole officer. He hit on her once, so he can get a better treatment but she punched him in the face so he never tried it again. Although she has magnificent body, she is lesbian and she is dating a shrink. This is were Marv gets his medicines from.
After Marv paid her a visit, Kevin came after her. He hit and drugged her while she was walking to her car. She woke up to his kitchen only to see him cooking and eating her hand. Paralyzed as she was there were not much to do. He had already cut it while she was asleep so it didn't hurt but he made her watch.
Marv found her in Roark's farm basement naked and in shock. Kevin was done with her for now so he locked her there. Marv passed her a cigarette and his coat and she calmed down. This is were he found out that Lucille was checking on Goldie and that in fact Goldie was a top class hooker.
Marv managed to broke the door and got them both out. By the time they made it to the surface, bribed policemen were there as well. Marv was ready to shoot them but Lucille stopped him by hitting him in the head with a rock, in order not to get both of them killed. It did no good and as soon as she told them were unarmed Marv was, she was shot to death.
Marv took revenge for her death.
Lucille was portrayed in the 2005 movie adaptation by Carla Gugino.