How do i send a friend request to someone who I only know the name of?

I want to send a friend request to a player named ‘Gantzer’ but I don’t know his email or battle tag so I can do it. I NEED HELP!

If possible, you might be able to look on "Recently Players’’ on the social tab to add him. But if that’s not an option, you won’t be able to add him as a friend.

You can search the name on overbuff, there are 3 gantzers in total. You can see their full btag. You also see their level so if you can somewhat remember their lvl border or player icon you know which one it is.