Kedar is another name of Lord Shiva the protector and the destroyer. Shiva, is considered the embodiment of all passions-love, hatred, fear, death and mysticism which are expressed through his various forms.
According to legend, the place came into being during the period when the five Pandavas brothers were asked to seek Shiva's blessings purging them of the sin of killing their cousins. Lord Shiva unwilling to give darshans to the Pandavas frled Kashi to live incognito in Guptkashi, where eventually he was detected by the Pandavas.
While fleeing Shiva took refuge at Kedarnath in the form of a bull and started to plunge underground when he was spotted by the Pandavas. He dived into the ground, leaving behind his hump on the surface. No wonder the natural rock formation that is worshipped here resembles the hump of a bull. Thus Shiva pleased with the determination of the Pandavas, exonerated them from their sin, gave them darshan & bestowed upon them the opportunity to worship his hump.