L's mother is someone as intellectually gifted as L himself. I see her coming from a wealthy family with sort of loving parents, but who don't entirely understand her. Her relationship with her son is unique; her understanding of her own son goes beyond that of a mother and son, but is also an understanding between two people who are equally brilliant. L is not a normal child in the traditional sense. He doesn't get along well with other kids, more of an observer than a participant, which makes other kids avoid him. His mother is somewhat of an outcast in her family, too. Coming from a wealthy family herself, she was burdened by higher expectations, so naturally, she sought freedom outside of her family. She finally gains her freedom from her family, finding someone she cares about, but unfortunately, she meets the wrong type of person who leaves her alone to raise a child. Later, she dies in an accident, leaving L utterly alone. I can also picture Watari, not being related to the family, of course, but at least being aware of his mother's existence to some degree, which would later lead to L and Watari's first meeting. I also tried to give her a wavy hair like L had in his first appearance in manga.
Mello's mother is someone who cares little about what other people think of her. She's a rebel in some sort of way, probably being a big pain for teachers when she was younger. Despite being quite young and inexperienced with motherly duties herself, Mello's mother loves him dearly, and maybe spoils him with chocolate from time to time. Mello's fear of being second-best reflects itself in something as innocent and naive as having a future sibling. Despite his mother's constant reassurance that she loves both of her children greatly, a young, childish mind associates it with the grumpy “if you get another kid, you'll love me less” kind of thinking. Unfortunately, his mom dies before he even gets to meet his sibling for the first time.
Near's relationship with his mother is the worst out of the three. I picture his mother as a reflection of Near's own tragic future. Near's mom is someone forced to be with a man she doesn't love, possibly even pressured by her own parents. She doesn't love the man she ended up with, but she has no choice now that she's having a child. Near's family would be financially supportive but would not care about his emotional state. If anything, he is neglected by everyone, especially his mother. For her, Near's existence is proof of her own inability to escape her situation; for Near, his mother's life is his soon-to-be tragedy. Burdened by the heavy expectations of becoming the new L, Near has no choice but to accept it and live as someone he doesn't really want to be. He doesn't hate his mother; hate is too strong an emotion for him to feel. In some way, he's maybe understanding of her. It doesn't matter now anyway. He has always preferred the company of toys over real human beings. It's too late to leave now anyway.
