They're formless and inconceivable. That's kind of their whole shtick.
Blizzard pretty much steals the concept of Lovecraft creations so might as well just have them be Lovecraft outer gods
#boycottchina
They have no shape or form.
They are just a shapeless blob of void that can have hands.
Just like a void walker.
Formerly known as Arafal
Huge all consuming beings of destructive energies without an actual physical form. Tendrils stretching far out through the nether, seeding their despair into the cores of other worlds.
FOMO: "Fear Of Missing Out", also commonly known as people with a mental issue of managing time and activities, many expecting others to fit into their schedule so they don't miss out on things to come. If FOMO becomes a problem for you, do seek help, it can be a very unhealthy lifestyle..
Something like Galactus. Everything important looks like huge humans.
I've always imagined them looking like how the Ogdru Jahad from Hellboy were described.
"We're more of the love, blood, and rhetoric school. Well, we can do you blood and love without the rhetoric, and we can do you blood and rhetoric without the love, and we can do you all three concurrent or consecutive. But we can't give you love and rhetoric without the blood. Blood is compulsory. They're all blood, you see." ― Tom Stoppard, Rosencrantz and Guildenstern are Dead
I always assumed they would manifest forms that looked similar to Pandemonius in Mana Tombs. The more powerful ones would have more human forms but look very unstable as they are having difficulties keeping their void power at bay or in a physical form.