My Ex's Boyfriend suddenly texted me saying he wants to fight

A little context, I broke up with my ex over a year ago and 2 months later her new boyfriend messaged me saying he wanted to talk about something I talked to him and cleared things up then we never spoke again. About 2 days ago I woke up to a barrage of texts from the new boyfriend saying he wants to fight and to pick a place and time and so on. I calmly asked him what's wrong and he kept being vague and told me he wants to fight. what should I do?

P.S. I didn't do anything, I didn't contact my ex, I didn't talk about him or to him, literally nothing.

Edit: kind of an update but I blocked him already, the fight that he was talking about is/was supposed to be on thursday or something so I guess I'll update more when that day comes.

Edit 2: clearing things up due to some comments. No I'm not a pedophile, I turned 18 in January and when me and the girl were dating we were both minors. No I did not abuse the girl, physically, verbally, mentally, emotionally. nothing. for more information, the girl should still be 17 turning 18 and the quy is either 19 already or turning 19 this year.