98-kun, also known as Hassan (はっさん), is the OS-kun of Windows 98, and the elder brother of 98-tan.
Like his sister Hacchan, Hassan also references Vulcan from Zatch Bell!. He can transform into his alter-ego Masked Vulcan, which has a blue suit like Hacchan's Vulcan. Back in the OS Wars, Hassan fought actively as Masked Vulcan, but after the war ended, he was often in the front seat of hero action shows, and worked as a pro-wrestler.
Nowadays, Hassan is unemployed and has not much to do, aside from going to the arcade and pachislots, and lives with the allowance from his grandmother. This caused his sister to no longer call him anything but "unemployed", though others still hope they can be close siblings again.
Art of 98-kun's Masked Vulcan.
- Windows 98, page about the OS itself that also lists alternate personifications.