Wdym since the early chapters??
Your confused there was never a demon king of salvation but nirvana and his group was known as the salvation
It's just a title given to him after he sacrificed himself when he became a demon king in the previous arc
There's no other demon king of salvation as safe to say (cuz kdj said it's a modifier similar to Lucifer's). KDJ claimed the "demon king" role from the previous scenario— then he go self sacrificed gaining the "salvation" title, it's a modifier he made because of his storytelling.
So now his constellation, tanto didnt have a name, has the modifier 'demon king of salvation'?
Yeap
I think i missed something. How dokja became the constelation demon king of Salvation when it existed since de the early chapters?