Ah yes, Yukari does support Maribel, in a creepy way.

Aren't they the same person?

No one knows for sure except possibly ZUN, and he ain't talking.

Hmmm...going over this to smooth out phrasing and just for my own benefit, I'm not finding a handy definition or clear context usage for おるし. While I can see it being used in the sense of "Oh, snap!" here, I'd still like to pin down its derivation.

Maribel is as much Yukari as Sakuya is a lunarian princess. It's just a fan theory that some fans pick up and run with, but which may or may not be trampled on at any time by ZUN deciding to make some canon that overrides or confirms it.

That's not to say that fanon doesn't have some say in it, however, as ZUN's original version of Patchy and Marisa had them as antagonistic, but Patchu/Mari apparently got enough support that ZUN decided to roll with it in Subterranean Animism, and make their somewhat love-hate relationship canon-ish.

Moonspeaker said:
I'm not finding a handy definition or clear context usage for おるし.

The Garasu no Kamen expression make it like contraction of "osorubeshi"
But that sounds like a weak argument :P

Actually, that sounds rather reasonable. I've never seen much of The Glass Mask. I wonder if the contraction is strictly from there or not.

おるし is a dialectal variant of いるし / 居るし.

Seika said:
The Garasu no Kamen expression make it like contraction of "osorubeshi"
But that sounds like a weak argument :P

Maybe you're mentioning about 'Osoroshii Ko'

Oh, so something like "There she is!" in this case. Well, as a general expression of surprise, "Oh, snap!" still works as an equivalent. Still, I'm a bit unsure of the grammatical use of し here.

Moonspeaker said:
Still, I'm a bit unsure of the grammatical use of し here.

According to
http://dictionary.goo.ne.jp/leaf/jn2/92431/m0u/%E3%81%97/

（終助詞的に用いて）一つの事実・条件を言いさし、結論を言外に暗示する意を表す。「旅行はしたいけれども、暇はない―」「せっかく出場させてもエラーはする―」

So Rinnosuke is saying, "She's there!", and implying something unsaid ("She's just teasing the girls," I guess?)

Oh, I know the usual application of し in the entry you linked; it just didn't make sense to me here.

why did i read that last bubble as "oh shit!"

You know, I wonder why Yukari is angry. Maybe she's annoyed she gave the girls a chance to get all lovey-dovey..?