|Windows XP Pro-kun|
|Common name||Windows XP Pro-kun|
|Also known as||Windows XP Pro, Saseto|
|Height||*none listed officially|
|System personified||Windows XP Home|
|Debut||25 Oct 2001|
|Latest release||5.1 (Build 2600: Service Pack 3), April 21, 2008|
Windows XP Professional was released alongside Windows XP Home and was aimed specifically at the business and school sector. It succeeded Windows 2000 and featured improvements to certain features, such as improved Encryption, and introduced new features, such as a new, more user-friendly GUI, faster boot time, hardware support improvements, Remote Desktop, new accessories and games, improved accessibility for disabled users, new system management utilities, handwriting recognition, Driver Rollback, expanded languages, and more.
XP was succeeded by Windows Vista in 2007, but XP proved to be so popular that most people either switched back or continued to use it. Microsoft released service packs for XP starting in 2002, and XP's support was extended to 2014.
XP-kun is a man in his late teens to early 20's. He looks older than his sister XP-tan despite being the younger brother, due in large part to his stature and well-developed muscles. Tall and muscular, XP-kun sports a long, brown-black braid, brown-black eyes, and scars on his chest forming the word "XP". His outfit consists of a collar, cuffs, and a long chinese-style loincloth all in the blue and white striped cuff pattern of his sister's outfit. (There also happen to be a few XP-kun variants, representing the different colour schemes available for the OS. They are shown as different characters, independent of XP-kun.) XP is brash but gentle, usually a nice, easy-going guy who just doesn't always think things through. He is very strong, but is kind to animals and children, and seems to respect people for who they are. Though he may be loud, he is just loud and cheerful.
XP is most commonly seen in the company of either 2k-kun or Pizza-tan. The former plays the big brother card, cheering him on when he spars and hanging out with him in his downtime. The latter seems to have developed a sort of admiration for him (perhaps due to her being a fangirl of 2k-tan, and 2k-tan having a crush on XP-kun), and the two commonly hang out and spar together. It is with XP-kun that the only pictures of an older Pizza-tan have been seen. As mentioned, 2k-tan has a crush on XP-kun, but it is unknown if XP returns these feelings, or who (if anyone) he has feelings for.
XP has also been seen in the company of his younger brothers Homeo and ME-kun. The former is usually just doing the typical poses or just hanging out. With Homeo, however, XP shares a special understanding, possibly due to them both having rather difficult sisters. He plays the regular older brother role here, being mischievous but not mean, and kindly looks out for and takes care of his little brother.