I would just like to apologize now for this horrible, horrible attempt at utterly geeky humor. (As well as for not feeling like making more than a full-color doodle out of what is, essentially, a throwaway gag.)
I knew someone in high school who played Warhammer 40K - specifically the Tzeentch faction of Chaos. I got sorta-commissioned to come up with color-schemes of sorts for some of his minis, including his Lord of Change, and brought along to games; I've never actually played but essentially have armchair familiarity with the setting.
The demon on the right is a Lord of Change.
To quote the Games Workshop web site: "To face a Lord of Change in battle is to stand against a master of fate itself. It unravels and deciphers what will come to pass, and uses the knowledge to confound its enemies' plans. The ultimate master of the medium of the Warp, the Lord of Change is second only to Tzeentch itself in mystic power. Its appearance reflects its capricious nature; the Lord of Change is a bizarre creature of multi-hued skin, massive feathered pinions and a bird-like face with eyes that shine with the ruinous light of the very depths of the Warp." So basically, skeevy bastard avian demon with glowing eyes that is horribly chaotic, prone to inducing insanity in others, that devotes most of its time to plotting and screwing with the plots of others.
The demon on the left is Nougami Neuro, from the manga Majin Tantei Nougami Neuro. He's a skeevy bastard avian demon with (intermittently) glowing eyes that is horriby chaotic, prone to inducing insanity in others, that devotes most of his time to screwing with the plots of others (and some plotting himself).