this is the first i think we have heard about his mother. i thought she was dead like we see in most manga but eloping with another guy leaving her kids behind boy what a THOT.
@RUD3DUD3 While the primary use for eloping is running away to be with someone or marry in secret, it can also just mean sneaking off. From the way the mangaka drew it, it really only suggests she ran off when the family's lifestyle changed drastically. Which is still pretty terrible, and makes her look like a golddigger so even if she didn't run off with someone at the start she probably is leeching off someone by now despite apparently still being married to love daddy.
@jespoke: What do you mean they got along fine? They barely interacted, and when they did it was almost always negative;
In chapter 25, she tells him it's sexual harassment to talk about the length of her skirt. She also told him to die.
And in chapter 39, again she told him to shut up and die, when he was asking about her visit to the student council.