if you COULD box this game, you WOULD box a Mystic who at level 28 can;

regen her own mana, create and drop mana and health potions in an area,
Mystic can also put out a speed and critical damage reduction area buff,
Mystic can also keep a pet around to pull aggro away while she's boxed.
in addition, this game has a "follow" feature so you could tether your
Mystic to your damage dealer as the damage dealer moves around.

the only problem is YOU CAN'T BOX THIS GAME... read my post above