The Cutting Room Floor mentions a few other demons who were cut from Nocturne besides that Amaterasu. Most of these appeared in NINE, but one named シャスティ (Shasty?) hasn't appeared in any SMT game. I would guess that this might be the Hindu goddess Shashthi. Either way, it's more fodder for unused Kaneko design speculation.
Similarly to Shashthi, there's a couple more unique names that popped up in Megaten Maniacs' Nocturne draft materials. I swore I've talked about them before, but I can't find it. Anyway, on page 95 there's a list on a page dated to March 1999 with these demons listed:
These are, from left to right: Leviathan, Behemoth, Tiamat, Humbaba, Set, Typhon, Angra Mainyu, Aka Manah, Azhi Dahaka, Balor, Surt, Loki, Fenrir, Jormundgandr, Chernobog, Chiyou, Mahakala, Vritra, Yomi Gozen, Ushitora Konjin, Lucifer, Satan.
So lots of baddies, mostly familiar names, except for Yomi Gozen and Ushitora Konjin! I can't easily find info about Yomi Gozen but Ushitora Konjin has significance in a fringe religious movement named Oomoto. It's obvious that this list was basically just a brainstorming session that never really came to pass for Nocturne, but intriguing nonetheless.