A net character, outside the core circle of OS-tans.
Her history is as follows: The Windows logo turned on the side looks a lot like the very common Japanese family name "Yamada" written vertically:
山 田
She was an early suggestion for a design for Windows 98, but never caught on because she was too plain. Nowadays she's mostly given up on being an OS and lives with WE-tan (who still wants to be one), Astaroth, and Spidey. She works as an OL, and has no distinguishing characteristics whatsoever. She's from Niigata, the most boring Japanese perfecture. She likes staying up late and watching TV.
She works at the same office as WE-tan/Taeko-san, 2k-kun, Eigyouseki (the businessman mutation of the super-deformed Suiseiseki), and a grown-up Hina Ichigo who's name I don't really know. Their boss is Darth Vader, who writes his name "米田さん", or "Beida-san".
