Isobel is an upperclassman in Iris Academy in Horse Hall. She's a relatively minor character, her interactions with the main characters being few and far between but she is well known for being kind, couragous and intelligent. It seems that she can speak English and Spanish fluently, though she can be a bit formal when speaking in English. She seems to really care about the well being of the freshmen, the most glaring evidence of this being when she defended Ellen from Angela's bullying in the Initiation.
She also seems to be good friends with Virginia, her brothers and Damien, if their friendly interactions shown in game are any indication of their relationships.
When failing studying late in the game, one of the options is "Seek Hugs", or "Blow off steam" (You run outside and shout wildy, Weird). Choosing Seek Hugs results in going to Isobel's room and getting a hug (+Cute).