This achievement is so easy, doesn't need any interaction between players (cause your friends request don't have to be accepted) and it will take you about 30 or 60 seconds.
You only have to log in with your account and click on any active game to see the in game players, then press right-click on any player portrait, finally click the add friend option... and you'll have your first Tochlight II friend and the achievement:
Repeat this an other nine times and you'll get this achievement.
Just repeat this an other forty times and you'll finally get the achievement: