Think about it: he was apparently devoted to her, was implied to have known her when she was younger, and seems to be very protective of her daughter.
- On my first viewing I kind of assumed Glitch would turn out to be DG's dad. He and LE have major chemistry. Plus, both of the girls look a lot more like him than like Ahamo. When they played the creepy-pedo-father angle again with Ahamo, it felt like a weird echo of the Glitch encounter, leaving me convinced for a while that Lavender Eyes/Glitch was the original intention and Ahamo was written in later.
- You are not the only one who concluded this very early in the storyline. I was disappointed... I love stories where you get to befriend your parent(s) before you know they're your parent(s).
The Prophecy about the sisters was flip-flopped
The prophecy said that "one to darkness she be drawn/and one to light she be shown." Everyone in the series seems to think DG was the light and Azkadellia was the darkness, which makes sense on the surface. But DG is the one who originally heard the Witch's call—Az only heard her after DG pointed it out. Also, while Azkadellia is the evil sister, in the end DG brings her back by showing her the light. So the prophecy was about the sisters, but switched around: DG was the one drawn to darkness and Azkadellia was the one shown to the light.