I know everyone else is going to go for an Original Character, and I was tempted to do one too, but ultimately I decided to instead add an absurdly customizable character from a series I'm a fan of. I'm referring to....
The Wielder of Light (Kingdom Hearts Union X)
Why the Avatars from Union X you're probably asking? Well, I think the level of customization that the KH Mobile Games give you would be able to translate perfectly into Console Wars. I mean, the basics could potentially just be the literal average Stats anyone in this game could have in this game, but with some level of Customization, as it would not only be their basic appearance you can customize, but also their Keyblades and Spells (Specials) you can customize too. As they would have plenty of Final Fantasy Spells they can use for Specials, 16 to be exact, matching that of the rest of the Roster. However, if this is enabled within the Settings, you can also have different gimmicks and stats enabled from whichever Keychain (Keyblade) your Wielder of Light has on their person at any given time, whether they be Keychains from throughout the Series like Ultima, Oathkeeper, or Oblivion, or some new Chains based around the current members of the Roster, such as some cool Keyblades based around God of War or LittleBigPlanet likely having the most creative designs. There is also a special option for Kingdom Key as well, which in combination with any of Sora's Outfits, will then unlock Sora as a Secret 52nd Roster Member, Voice Included. Yes, these Special Sora Combinations have their own recolors and completely ignore the setting to turn them off. As for their outfits, while in the Union X Titles they're primarily based off of Disney, Final Fantasy, and Mainline Kingdom Hearts Characters, I'd imagine only the latter two would be able to fly within Console Wars, due it being a celebration of Gaming History, but in its place, are a LOT of Outfits based off the Characters who couldn't make the playable Roster. I already mention Sora earlier, but you could also get the Dress of Peach and that Mario-Themed Keyblade to make a Peach Cosplayer. Or you could bring in a Keyblade based off of The Last of Us, and add Costumes based around Ellie and Joel. Heck, there would even be a Garreg Mach Student Outfit, and likely a Keyblade modeled after The Hero's Relics, and then you could potentially add someone like Hilda or Sylvain to the Roster. Honestly, the possibilities are limitless, which is why I think that The Wielder of Light, from Kingdom Hearts Union X, would be the perfect avatar character for Console Wars. They even have the perfect excuse to be here, as Kingdom Hearts is a series that takes place within a World of Worlds, so let's just say by some unknown means, the Wielder of Light ended up within the Multiverse of Kingdoms, unable to leave because how they got there being a One-Way Trip. The only additional note is that they'd be slightly taller than Sora, and be in the Normal KH Style, instead of the Chibi Style of Union X, but can also be made Chibi as well, which is the exact same size as Sora because Customization on Avatar Characters is based. Anyways, That's about it, for now, hope y'all liked my concept.