Keep follower with friends

[Rguy]

Usually when a friend joins your game you follower will leave, however if you are in the middle of combat he won't leave until your taking a break ( like the counter of kills stops )

So just:

1. Play alone with a follower
2. Engage a hard fight for example champion packs and dont stop attacking.
3. Invite your friend
4. He can TP to you and help you kill the champions while your follower is up. ( until combat timer resets )

[Muramasa]

It's not really keeping the follower though. Keeping implies they will stay post-combat. What would be better for thread would be:
"Extra DPS on rare packs"
1. Find a special/rare pack
2. Get a follower from town
3. Engage the rares.
4. Invite your friend(s).
5. They can TP to you and help you kill the champions while your follower is up. ( until combat timer resets )

[Gbyrd]

And once you tap it the champion mobs they dont scale or change hp if i remember correctly to scale with the new hero that joined