I haven't watched Re:Zero before, so I used the introduction and some skim reading from the wikia to base my understandings. There's bound to be error. A lot of it, for me, was down to interpretation. You can look at a succubus being something like an artificial spirit as they're born form a desire or strong emotion.
(According to my retconning backstory)

[@ADamnFiddle]
Your help with magic and divine explanations would be appreciated.

Edit: This is no big drama for me, I want to join the RP and will happily work through the problems in my character to make something suitable to the RP and setting. I just felt like there was a lot of leeway in this RP. 

Double Edit: In addition, placing a race in is kinda simple, you don't need to make a note of their existence and can create assumed knowledge already being implied, unless you want your character to state otherwise and ask for an explanation on what a race is/where they come from