Youmu: I'm the ghost princess and there's no soul I cannot cut Suwako: Real Suwa Field Chen: Spinning ball that can go through gaps Reisen: "Doctor, you can't save me at all. It seems like the only thing you're good with is your sex appeal" Nazrin: I am Youkai Mouse Christ since I'm Nazrin.
The common link is not "servant characters", it is the parent post. These charming young maidens are wearing the clothes of the... other charming young maidens... who borrowed their outfits.