First is family. The majority of the de rolo family was slain save one sister who was only recently discovered to be alive. As such her and percy's relationship is very close as the pair of them have been through so much lost so much not n111ecessarily together but pain loves company.
Next is his dear friend keyleth. He is a dark reason man where as she is the doe eyed wild child. She lightens him up and he brings her back down to reality. They don't make a lot of sense outside of that but they're good together.
Lastly we have the love of his life vex. She grounds him out of fits of rage and harsh hasty movements. He is often awe and inspired by her even when doing basic haggling.