However with grim reaper, an additional 12% of damage done to the target is also divided among all enemies within 20 yards. Barbarian and wizard can deal easily over 200 000 000 and its 12% of damage, which is 24 000 000 is dealing to the mobs around. But you can deal this damage to mobs only when you kill the mob that got grim reaper with sever and when there are mobs within 20 yards.
It would be ideal to form a party with a demdon hunter, hammer of the ancient barbarian,
cm wiz, and a cyclone strike monk, but only with a dh and barb will still work if barb kill weak mobs and dh use grim reaper on top of it with control.
Here are few videos that I've searched on youtube.
performed in mp7, but i bet with this combination, people can easily do mp10.