Original Ask: Can you write something with Sero, Iida, or Shinsou comforting/dealing with an S/O who is being harassed by a family member?
Iida Tenya: Iida is likely to confront the family member directly if you don't protest, because he's not a fan of disrespect, especially among family. He may seem to drone on on a point that seems like common sense but it's proof that Iida regards you highly, and that it genuinely upsets him to see someone 'close' to you treating you so poorly. He apologizes later if he was too confrontational, but there are some things even he can't just let pass.
Sero Hanta: Sero had no idea what he was walking into, and he's not a real fan of it when he sees you being harassed. He tries to subtly create some distance between you and the family member that, and when that doesn't work, he quickly comes up with a rash escape plan that leaves your family member fuming. He wraps tape around their mouth and quickly pulls you away, making a run for it and happy to see a smile on your face as you laugh about how much you wished you'd come up with the idea instead.
Shinsou Hitoshi: Shinsou would interject himself into the conversation, seeing that you're clearly uncomfortable and assumes you wish to leave the area to get yourself together. He says something incendiary to the family member to get them to respond to him, and quickly takes advantage of his quirk, having them leave the room at a far enough distance that the two of you can get away without having to deal with more harassment. He asks how you're feeling, not minding if you don't want to go back and put yourself into that situation again.