The K98 bayonet is actually the Mauser Karbiner 98 Kurz bayonet. The longer name was appreviated to K98 bayonet. The K98K was designed to be used with the S84/98 III bayonet. A later version of the K98K did not include a bayonet lug, so the bayonet was no longer used.
The Karbiner 98 Kurz became the standard issue rifle for the German army in 1934. It remained in service until the end of the war in 1945. The K98K was one of the best bolt action rifles of it's time. This makes it one of the most sought after military rifles. This rifle was used in many wars and is still in use today.