Mary Skelter is not a lewd dungeon crawler RPG series just because you can put the characters in revealing outfits or because there's a minigame about washing them.
To me, the horniest thing about it is actually the fact that one of the central mechanics has to do with managing how much blood your party is covered with, with characters having the ability to either lick the blood off each other or cover their allies with special, purifying blood.
And you need to do this because if one of the girls gets too bloodied while also having a high level of mental stress (such as if they just took a ton of damage or if an ally got knocked out) then they lose to their inner bloodlust and transform like this.
The thing that made me play it initially was actually this focus on blood. It's a given just from looking at my url that I'm a big fan of blood in general. It also helps that I like things like DRPGs and fucked up ultra-dependent romance too.
Today I’m dropping art of Hameln from Mary Skelter! She’s a real goofball and I absolutely love her! I’m dedicating this month to Mary Skelter cuz I just can’t get enough of this series! I’ve got lots of cool ideas so please look forward!