It’s really strange. When you start looking at it from a distance, both Mega Man and Sonic the Hedgehog fandoms share far too similar things. Namely, strange obsession to make their own characters by recolouring existing ones, coming up a low quality bio for them and making the most powerful beings in the universe. It’s even sadder when things get official.
With the Truforce Mega Man X toy, we’re getting what essentially is a licensed fanfiction character in form of X-Kai.
X-Kai’s whole backstory reeks of fanboyism and mary sue. Tied to the original Mega Man’s stolen blueprints, X-Kai was given higher stats than X with cutting edge tech. This is of course bullshit when it comes to the lore. Wily didn’t have a need to steal Mega Man’s blueprints, he was an accomplished robotics scientist himself, building far superior robots and war machines by himself. Hell, Bass is a straight up imitation of Mega Man, and the reason why the Blue Bomber wins is not because of his tech specs, but because he has something to protect. That’s stated in the games themselves, dammit. Would Dr. Wily stoop as low as copy Light’s work to make enemies?
Capcom has a history with Mega Man and doppelgängers. The above examples are from Mega Man 1 and 3. Copy Robot is exactly what Mega Man is, and in Powered Up he gets an upgrade in his functions to copy any robot character. Holograph Mega Men don’t replicate the weapon usage, but can shoot in any direction they want. Furthermore, Mega Man has a Shadow counterpart that’s a common enemy in Plug Man’s stage in MM9.
Mega Man X himself never fought a true doppelgänger in the games, mostly because CAPCOM was too busy making characters that weren’t repaints of the same character. However, we have Return X/ iX from the Cardass Mega Mission card series, who fills that place just fine.
Keisuke Mizuno is the designer of Truforce’s Mega Man X, who came up with the concept and realisation of X-Kai. It is technically true that CAPCOM has never produced a doppelgänger for X. Bandai has, and he has followed Bandai’s footsteps. Hell, X-Kai even shares similar lines under his eyes with Bass and Return X. Mizuno’s idea is not original.
Both X-Kai and Return X fill the same spot as Nemesis Prime does in Transfomers; the reuse of existing assets. X-Kai is repainted Mega Man X with a new bio. Return X similarly uses the same basic frame of the Mega Armour series X, but bolts new parts on top of it. If you remove the extra parts off, you’re left with two toys that share 90% of the same parts.
As a sidenote, the Mega Armour model toys are pretty damn great, I used to have a few before they got broken during one of my moves.
The rest of the franchise has seen other evil duplicates to boot. First ones that pop into my head outside Classic and X-series are Battle Network 4’s Shadow Mega Man.EXE and Omega from Zero 3.
Doppelgängers are not bad from the basic idea up, but they have been used in anywhere and everywhere to the point of them becoming completely stale, like a ten years old soda that was left open. It’s not to say that a doppelgänger could not be done well, but it needs to have an impact outside that goes further than Evil Twin or Nemesis Counterpart.
Castlevania is chock full of the most basic variants of doppelgängers ranging from basic character copy bosses to Mina’s bait copy in Dawn of Sorrow, but the best use of character-copy enemy in this nature comes from Symphony of the Night. In SotN, you fight fake version of Trevor, Grant and Sypha in the Reverse Colosseum. While the description says they’re zombies faking their appearance, they act like any other Evil Counterpart variation. The reason why this threesome boss fight is well done is rooted to the fact that the three characters Alucard is fighting are twisted versions of the same characters the player played in Castlevania III back on the NES.
A Doppelgänger needs that kind of treatment. It needs to be more than a simple evil version of a character fighting the original. X-Kai essentially replicates what Bass is to Mega Man, and that’s lazy and pathetic. Much like with the whole cooky cooking Inti-Creates made up to solve the Maverick wars and explain things, X-Kai is in no form any more official or canon than those tidbits or Return X.