Call the police or something. But if necessary , kill them first , defend yourself.

Act dead bruh

Inform the police, I'm sure you'll be kept anonymous so as to protect you from further threats.

Report their ass to the police!

First get them to threaten you and try to record it in some way. If things go South this can be a good evidence for your lawyer. Then get some kinda concealable weapon. Then start to study the person's daily routines. Better yet find out if he has any allergies, if he has other enemies, if he uses some dark alleyways, if he uses public transport or prefers private chauffers like lada etc. You can really find out a lot of weakness in 2 or 3 week. During this time it's vital that you avoid any kinda contact with him. After that if you decide to take action get your family somewhere first then try to disguise yourself before doing your last move and then get rid of him. After that dig a 5 meter grave, bury him, fill the soil to 2 meters, kill a dog bury it and then fill the rest of the grave. Then try to make the grave look like a normal ground. If someone is suspicious and dug it up they will think that it's a dog's grave. But if they dug more and found the body and somehow its linked to you, you have his record threatening you so you will say it was an act of self defence. Or you can just go to the police.

Run

Kill him first😎

report it to police, your identity wont be known

Kill him😕

Ill fuck his mom and be his father then ill ground him for life