In an abandoned SciLab laboratory that used to carry research on the Cyberworld, its server was restarted, possibly to be secretly used by Dr. Wily after he left SciLab. The server was left on for years, and Cache was born from its large Cache Server. Cache has a dislike humans due to their past actions, and uses cache data to make humans remember the destruction and horror they caused in the past. He attacks the world with copies of NetNavis and his creation JammingMan.
Cache is eventually found by Lan and MegaMan in the old Cache Server. After his defeat, he summons 10 JammingMen to cut the communication between Lan and MegaMan, saying that the connection between humans and NetNavis is weak. MegaMan explains to Cache that he is Lan's brother and they have a strong bond, and they manage to contact through the interference. Cache is unable to believe on such a strong bond, and gathers a large amount of cache data from the server to his body, increasing his power, but is deleted by MegaMan. Before vanishing, he notes that as long as there is forgotten cache data around the internet, a new Cache may be born. With Cache gone, the Cache Server collapses.
In the anime, Cache was the one responsible for creating several duplicates of NetNavis (A.K.A Phantom Navis) using the cache data accumulated in the Cache Server, where all of the world's cache data is accumulated. He can apparently turn NetNavis and humans into cache data to gain power and seems to not be in agreement of how NetNavis and humans work together.
He firstly spreads Phantom Navis around the world to wreak chaos and terror, and used the disrupting radio signals from JammingMen to create fake perceptions of reality around people. Things escalate when Cache sets up a JammingMan within SciLab's Network to block all jack-in and jack-outs around the Cyberworld. After MegaMan, ProtoMan and SearchMan destroy it, he reveals himself and begins to transform all objects and living beings in the world into data to assimilate into himself.
In the end, however, he is defeated by both Lan and MegaMan in the final episode, thus bringing an end to the series.