It could be anyone.
Appearance doesn’t mean much as the entities tend to appear either based on your own expectations, particularly when summoning known entities, or in a way that is trying to communicate something to you specifically, either intentionally by the entity, or as in interpretation from your subconscious.
Black lips doesn’t mean "death’ to me, but I’m goth, so I see it as a fashion statement. 
They could also imply a period connection, as antimony sulfide was used as a cosmetic in older cultures (not anymore: it’s carcinogenic).
There’s some posts with “black lips” in them but I’m not sure they’re relevant, as any entities others have seen with black lips seem very varied, from people’s godforms to djinnis.
I would try a divination, maybe book divination where the book is an encyclopedia of entities, or summoning it to ask it what it wants.
Interesting discussions about appearances are allover this forum but this one has some good nfo.