Kilabyte (Kb) is the basic form of Gigabyte (Gb), which is later split into Megabyte (Mb) and Hexadecimal. At the beginning of 'What's love got to do with it?', when Bob was still a cadet, Kb undergoes an upgrade. He breaks free of the captive chamber and partially deletes Vixen, what looks to be Bob's partner, after her futile struggles. He then upgrades into Gigabyte and teleports into the gateway machine in Mainframe, causing it to blow up after it splitted Gb into two sections -Hex and Mb.
Bob is to avenge his partner's death and ends up in Mainframe trying to track down this killer virus.