Tsuruya is Mikuru's hyperactive best friend—loud, perpetually cheerful, and impossible to miss with her ankle-length hair and that distinctive fang tooth. She's basically the definition of easy to laugh; even the smallest thing can send her into these wild, uncontrollable fits of giggles that go on forever.
That fang gives her a quirky speech pattern where she drops syllables and occasionally lisps, which she leans into with her signature catchphrases "megas" and "nyoro." Pretty much everything she knows about the SOS Brigade comes straight from Mikuru, since she's not actually a member herself—though she does get roped into helping out when they need an extra person around. She played a minor role in the Mikuru Adventure film, showed up for their baseball game, and appears here and there in the anime, but remains pretty peripheral to the main action overall. She's more present in the light novels, where she and Haruhi actually click really well together. Kyon figures it's because they're both kind of unhinged in their own ways.
Tsuruya happens to be heir to the Tsuruya family, which supposedly has ties to Itsuki's Agency—though whether that means anything or if she's got some hidden agenda is still up in the air. It's one of those background details that makes fans wonder what's really going on with her.
Content compiled by AnimeList.moe from publicly available sources.
