horrible 'friend'

theres this person in my friendship group who is just the nastiest, most aggressive, rudest person ever. sometimes they border on nice but those times are very transient. they think everything they say is the truth. they are very argumentative to the point that we all have to back down whenever they say something even if its objectively wrong. if you try to defend yourself or someone else they get equally defensive and make out you're some overreacting monster. and no one in my friend group really talks about it because we're all very tolerant and they've been in the group for years even though every person in the group i talk to about it dislikes them. one time they were just outrageously rude to me for no reason and no one stood up for me which hurt me deeply. they have basically bullied everyone into submission and i feel like i'm about to snap. there's not loads of school left but i am just at a tipping point and feel like there might be a huge argument before the year ends which would be worst case scenario. should i leave my group chat to lessen the chance of this? im just not sure what to do