User blog comment:ND999/Daemons of Runeterra/@comment-5035765-20150709232505/@comment-25996306-20150712223037

Well, the general concencus is that Eve is a vampire of sorts. If we look at the True-Blood vampires of Skyrim, they're undead with heavy demonic influence (if you count Daedra as demons).

Even doesn't seem to meddle with mortals in the same way that the established demons do, so I guess you can count her as a minion, which sortof puts her in the same position as Varus, as discussed by Filheinzand Persephone04.