Like many of Path of Exile's expansions, Delirium is all about players challenging themselves on their own terms and deciding how much (if at all) they want to play with its new systems and quirks. When Delirium releases on March 13, players who start a new character in the Delirium league will find fragmented, creepy mirrors scattered throughout the world with a hazy mirror image of themselves visible just beyond them.
Stepping through will transport you into a foggy parallel dimension. For about a minute, you’ll be beset by horrific new monsters and strange fog-borne mutations of existing foes. These hordes are much tougher than the normal rank-and-file critters, and the further you push out from where you found the mirror into this strange new world, the harder things become. Powerful new mini-bosses lurk on the periphery of these mirror dimensions, but that's exactly where the best rewards are, too.