[quote=@Dr Lovecraft]
So, what qualifies as 18+? It says "adult themes" but like... death is technically an adult theme, and death can be found in the most kid friendly media. I'm assuming it's more like an R rating or an M rating? More drugs and sex than anything else?
[/quote]
18+ usually applies to graphic erotic content (ex: "smut" or "ERP"). This, for example, is what the rules of the Guild apply to. What ELSE falls under that umbrella tends to vary from person-to-person though. Sometimes people also just use the 18+ tag to mark that they don't want to write with minors for miscellaneous or comfort reasons as well.

Hope that answers your question.