[backendsbelike]

Some unethical life advice, he is being unethical so you can be too (with him).

Strategy 1 Find his weak point, and hit it. Make fun of his weak points, is he short? Don't accept his PR, make him beg you to stop - now he wants something from you.

Strategy 2 Ignorance is a bliss, threat him like he doesn't exist, don't talk to him on calls, don't mention his name/work. Don't listen to him.

Strategy 3 Call him out publicly. Be prepared. Is he claiming your work, ask publicly in how did he do it and how does it actually work. Act very interested, make him show the commit. Waste everyones time, don't care.

I know this is all toxic stuff, and you may not want to engage, but you are being hurt and forced to change work. So it's about time to change the strategy.