Simon's parents both died in a cave in when he was 7, right in front of him, and he wasn't able to do anything about it. He cared about them a lot, and still does to this day. When they died, it changed a lot in him, turning him into somewhat of a coward, and pushing him on a path to being a doormat. His foster father was the Chief of the village, who, headcanon (backed up with evidence from the show) says abused him. And it wasn't just physical, it was largely verbal/emotional. He misses his parents, and they're part of what drove him to really start fighting the beastmen. Knowing they were what killed his mother and father gave him just enough rage to use Lagann that first time, and I think it was a factor all the way to the end.

Fuu loves her parents. There's no real canon about them, so this is all made up. Her mother spends a lot of time overseas, and her father is a business man, so she doesn't see them often, but she knows they would do anything for her, and she'd do anything in return. She pushes herself so hard to get good grades for them, and almost them alone. She's managed, thus far to not disappoint them, and is greatly fearing the day she does.

Aigis is a robot.