Copycat Ken is an anime only character who's a notorious thief and bane of the greater Tokyo area. He is well known for his ability to copy and use the abilities of Martial Artists that he's observed.
Ken arrives in Furinkan and begins to photograph Ranma as he fights various opponent one evening and the following morning. While Ranma talks about his being stalked, he notices that Ken is still following and photographing him. Ranma charges at Ken, but he dodges and warns Ranma that he'll be back before jumping across several rooftops. Presumably about this time, Ken also faced Kuno and Mousse by copying their techniques.
That evening, Ken faces and defeats Ryoga then taking his identity so he can face Ranma. However, Ken might look like Ryoga but he doesn't have the same personality so his actions make Ranma very suspicious and Ken's cover is quickly blown when the "true" Ryoga if found by Ranma in a nearby trashcan.
After turning from Ryoga back to himself, Ken then turns into Ranma and the pair begin to fight each other. Akane soon arrives and is faced with two Ranma's, with each declaring the other to be the fake. The true Ranma tries to uses his "Katchu Tenshin Amaguriken" to prove his identity, but Ken is able to copy it exactly. Ken then defeats Ranma using his copied Amaguriken and grabs onto Akane's waist, only to be attacked by an angered P-chan.
As Ranma leaves to go do some training, Ken finds Happosai and begins to copy him as well (only this time he also copies Happosai's personality as well, such as going on panty raids and jumping at the sight of Akane). After being swatted away by Akane, the two talk to each other. Happosai notes that Ken's skills are impressive but still have their limits. Ken then reverts to his true form and asks Happosai if he can be his disciple, to which Happosai agrees to. The pair (with Ken back to being Happosai) terrorise the Tendo Dojo with multiple perverted antics, much to the annoyance on Akane, Nabiki and Kasumi.
When Ranma eventually returns from training, Ken disguises himself as Akane so he can get close to Ranma. After being punished by Akane for taking her form, Ken and Ranma begin to fight each other. Initially Ken is unable to keep up with Ranma as all the fighting Ranma did with Ryoga, Mousse and Kuno has actually improved his fighting skill somewhat. Struggling as his true self, Ken resorts to his copying tricks to try and regain the upper hand.
Ken starts by turning into Ryoga and then Mousse, which gives Ken a minor advantage in the fight. He then makes the mistake of turning into Kuno, Ranma's weakest rival, and is subsequently taunted for doing so. Ken then proceeds to turn into Happosai. Akane then helps Ranma by throwing cold water over him and thus turn him into his female form. As Ken also copies Happosai mannerisms, he immediately latches to Ranma's chest, allowing Ranma to hit him over the head.
The fight continues and Ranma begins to struggle against Ken in his Happosai guise. Ken then turns into Ranma's female form as well. At this point, Ranma remembers what Genma said about how Ken only has the power which you give him. This makes Ranma try her Katchu Tenshin Amaguriken again, only this she focuses so much she reaches a level that Ken can't mimic. This literally punches Ken out of his Ranma guise. He then gets up and tells Ranma to prepare for his most terrifying transformation trick. He then changes into Ranma's rivals in very quick succession, but soon gets them mixed up and can't stop himself. Ken then asks Ranma and co to help him as he can't stop, however, the others just look on.
Ken makes a cameo in Tendo Family Christmas Scramble.
To be added
He is a selfish, malicious soul who uses his mastery of Copy Martial Arts to humiliate martial artists by beating them in combat, as well as sullying their reputations for amusement. He also apparently uses the identities he copies to commit acts of burglary, and had become quite well-known as a thief throughout Tokyo. When he decides to spread his spree to Nerima, he ultimately meets his match in battle against Ranma Saotome.
Other than copying the appearance and techniques, Ken isn't shown to have any talents unique to himself. He is, however, able to copy techniques of those who he has observed being able to copy Ranma's "Kachū Tenshin Amaguriken" with a skill which initially passed that of Ranma. Ken is also shown to be able to copy the "Bakusai Tenketsu" and "Happo-Fire Burst" while in the guises of Ryoga and Happosai, respectively. Ken also claims to have a "terrifying" technique involving using multiple guises in quick succession of each other, however, Ken doesn't seem to have mastered this technique.
The only character who treated him somewhat nicely was Happposai, even then this was mostly since having a pupil who could turn into him allowed Happosai to try more daring (as well as more annoying for his victims) perverted antics.
Due to his copying other Martial Artists' techniques, Ken gained a reputation and became the bane of all the Martial Artists in the greater Tokyo area who knew of him. Because of other Martial Artist viewing him negatively since he only copied the techniques of others as opposed to learning his own, Ken doesn't seem to get along with other people, other Martial Artist especially.
- Ken's martial arts style, Copy Martial Arts, is only mentioned in the original Japanese version.
- Ken has the unique distinction of being the only rival character who Ranma, Ryoga, Mousse and Kuno have joined forces to try and defeat (although the alliance between the four is short lived).