The Demons Bible is the gift that keeps on giving, this time a lengthy interview with Kaneko Kazuma about his inspirations, demons, their appearance in his art and the Shin Megami Tensei series and a nice explanation for Nocturne’s Vortex. (lots of thanks to eirikrjs)
Some more Demons Bible related stuff here: guest artist demon designs; Kaneko’s comments on his demon designs from Shin Megami Tensei III; mythology behind a few demons (Sakahagi, Manekata, Mizuchi, Kikuri-hime and Arahabaki).
More Megaten translations here.