Eh, honestly, I find a lot of the MGE's lore weak and its designs too close to cosplay, personally. I definitely give it credit for helping me really get into this fetish, but I've done a lot more with monstergirls on my own end.
And since there's such a positive reception, well, maybe I'll share a few idea that I've had flit through my mind, hmm? Fair warning, I've been told my tastes are fairly eldritch...
These are all kind of bare bones, but hey, this is just off the top of my head. I'm sure we could devise something more from one of these if folks liked her.
#1: A lusty troll witch in a swamp or a forested mountain's cave somewhere. She offers assorted special alchemical brews, both in the "healing potions" sense and in the "reliable sexual boost" sense, but you gotta offer her something worthwhile in trade. Fortunately for you, she doesn't get a lot of loving, and she's willing to trade for that. Femdom, maybe potion-related sex. Perhaps go the whole hog and make her focus more on life/fertility related magics?
#2: A spunky spitfire goblin pyromancer... like, imagine if Tamani from CoC and Lina Inverse had really hardcore drunken lesbian sex and made a baby. That's basically what this girl would be like. She could be an established NPC, such as a bandit queen type, or perhaps a follower if she took off well enough.
#3: A Hydra-girl. Essentially a scaly-skinned lizard-girl with draconic horns, a pair of "maw-tentacles" (tentacles coming from the back, each tipped with a snake-morph's head) and a "tail-maw" (like the previous, but placed where a tail should be). Huge appetite for semen and breast milk. More of a unique boss monster, potentially tameable as a pet if you manage to keep beating and feeding her?
#4: An owl or raven based harpy. Shy, bookworm type who has access to a stockpile of tomes you need somewhere. A blushing virgin but also a huge covert pervert, so very easy to seduce her, but watch out, because she's surprisingly aggressive in bed once she gets over the shyness.
#5: A "sahuagin" (sharkgirl/lizardgirl hybrid) sailor/smuggler who hangs out in the Maiden's Bane and occasionally relaxes at the lake near Rigard, possibly in other locations along the river if they end up existing. Hard-talking, hard-drinking, hard-fighting, hard-fucking ladette. Sort of a cross between Miranda and Cassidy, sexuality wise.
#6: A female golem or living doll maid you find stranded in a wizard's tower. She's been abandoned for a long time as a "defective product"; she's obedient enough and very loyal, doing everything she should, but she's snarky and sarcastic rather than the bimbo personality she was supposed to have. She might be a potential non-combat recruit to help out around the gemstead, or she just might be willing to shag your brains out if you'll let her leave the tower.
#7: An "ettercap" (four-armed, four-legged spider-girl). Not really sure what to do with this girl as a character, but I know she's someone I want. Maybe a kunoichi style character theme? Sexy ninja warrioress?
#8: A catoblepas (magical cowgirl with killer eyebeams/breath weapon) bandit chieftain who has been terrorizing the region you find her in. Defeat her or bargain with her.
#9: A basilisk, rendered as a cyclopean snake-girl or lamia. Cool, regal mystic who makes use of mind control themes when mating with you.
On the naga/lamia debate... it's really become meaningless in modern monstergirl fandoms. There's maybe a slight prediliction to using "naga" to mean "vore fetish snake girl" (courtesy of Felarya) and "lamia" to mean "no vore fetish snake girl", which is ironically the wrong way around. I've also seen nagas with a tendency to be armless snake-girls.
