somehow, i don't think that's tsukasa...
also, that box in the background is from Ragnarok Online. tag added

its not from ls
tsukasa has black eyebrow
diferent color of hair/eye (lighter)
and shorter

I'm pretty sure she is from RO itself, but not sure from which class. Looks a bit like a priestess, though.

I found it in a Tsukasa thread, but you guys are probably right. Her breasts are way too big for it to be Tsukasa.

The "box" is a monster of RO, Myst Case. I add the tag.

Well, some japanese hentai sprite site made once a human version that did look like that.

yeah, the fanmade hentai sprite had a girl inside that box.