Sounds like Dracula's 2nd form in most games. Was this for LoS1 or LoS2?
It was LoS2, I believe. It shows buffed up Satan and right next to him the multi-headed dragon(which is a reference to the Book of Revelations). You also see the The Beast in Ayami Kojima's artwork for CoD behind Trevor:
Though, that particular artwork also has the human-faced locust(another apocalyptic creature), and made me think that CoD was also going to have some "end of the world" themes(would've been cool if Dracula tried to bring on Armageddon in the late 15th century AS the original canon's version of "the devil"). I mean, hell, seeing that poster and that imagery(including Cerberus), lots of hellish creatures, I thought they were going to be bosses(and CoD WAS going to have an apocalypitic tone). Another reason I thought this was because the Minotaur is on the poster, and he WAS a boss(I think the Wyvern's there too, as well as Crazy Armor, as he seems to have a similar bloodstained look as the boss). I kinda wonder if IGA DID have more ideas in store for CoD, but had to cut a lot of it due to deadlines and... poor level planning(LOL).