So, basically what this guy does is the following:
1. Stacks insane amount of toughness.
2. Pulls all mobs (elite packs aswell) and put them in one area.
3. Since he so much toughness he will never die.
4. Invite people into the party and wait until they teleport to you, aka. death.
Please do something to this guy.. report him, or anything. Just don't let this guy keep playing this game.
TL;DR : A russian streamer on twitch purposely kills HC chars for the trolls.