Xander, who'd been cursing his rotten luck just minutes earlier, was now quite happy with the bargain he'd been able to acquire from Ethan's. His plan had been to buy a cheap toy gun and combine it with old soldier fatigues he had at home, but there had been no such guns left, forcing him to alter his plans.
Evidently the shopkeeper had seen him at the bargain bin and after a few minutes conversing, had offered him a deal. He had several costumes in the back, not displayed because they all had manufacturing errors, sometimes several and something had spilled on the box. Xander had shrugged at that, he wasn't entering any contests where such details would matter, so he easily agreed.
Well, to call them 'costumes' would be a bit too generous, what he'd bought was more like a box of costume accessories. Several forehead protectors with inverted or mirrored village symbols, incomplete weapon sets, wrongly colored sharingan and byakugan lenses, a ripped flak jacket (with a big stain on it)...
As he browsed through the box, he began to create his character. Within the Naruto-verse, Xander had (to date) two main favorites. One of course being the main character, Uzumaki Naruto. The second was his teacher, Hatake Kakashi, or as he was also known, Sharingan no Kakashi.
Creating characters with elaborate and/or intricate backstories was something he had always enjoyed doing with Jesse. And while those memories were now bittersweet to him, he still liked creating characters like this.
Like Kakashi, his own character Uzumaki Arashi, had a sharingan implant. As an Uzumaki however, Arashi wasn't bothered by the chakra drain of the implant, but he had been bothered enough by the 'always on' state of it that he had turned his sealing arts to the problem, leading to the creation of the 'doujutsu integration seal'.
As the name implied, the seal integrated the implanted doujutsu into the host's physical and chakra systems to the point the host could use it as if born with it. It didn't make the implant reproducible though, just controllable. Even so, the sealing technique had immediately been classified as an S-rank village secret!
Eventually Arashi had managed to unlock the mangekyou sharingan, awakening tsukuyomi in that eye. From there Arashi had eventually managed to develop, and implant, another genjutsu technique that basically did the same as Shisui's kotoamatsukami, a mind control technique.
That not all Uchiha agreed with the clan's decision to let Arashi keep the implant, was proven on one particularly difficult mission. Arashi's team was ambushed by a lone Uchiha, one capable of wielding amaterasu and willing to use it against his fellow Lead nin.
Arashi sustained grievous wounds before sacrificing his sharingan by casting izanagi, in order to save the life of his second teammate, after losing the first to an amaterasu ambush. That sacrifice threw their attacker long enough for the saved teammate, a medic, to land an instant kill hit on the rogue Uchiha. Said medic felt no guilt whatsoever as he used the traitor's corpse for donor materials to fix up Arashi after the battle.
Aside from a new sharingan, Arashi became the recipient of the Uchiha's heart, a lung and the entire left arm and leg. Entirely unexpected, the original sharingan implant had been integrated well enough to trigger the awakening of an eternal mangekyou sharingan within the newly implanted eye. A band narrowly encircled the pupil, with six tomoe orbiting further out was the eye's seal.
It was only Arashi's Uzumaki lineage that allowed him to survive the encounter, but even so, he was fundamentally changed. With such a large percentage of his body replaced, Arashi had to essentially recreate his chakra by fusing his Uzumaki chakra with the Uchiha chakra of his replacement body parts. That nearly killed him all over again though when he was done, the integration seal had dissolved, having become obsolete. Arashi had in a real sense become an Uzumaki-Uchiha hybrid, as if born from an Uzumaki and Uchiha parent.
Arashi found he could now summon susano'o, despite only possessing a single sharingan. Xander decided that being of Uzumaki descent as well as having the eternal mangekyou sharingan would make up for the missing second sharingan.
He further imagined Arashi recreating swift release and dust release through pure training, as well as creating the unique inferno release by combining amaterasu with wind nature transformation. Naturally, senjutsu training couldn't be forgotten, via ancient Uzumaki/Senju training techniques. Xander then shuddered briefly as he imagined a dust release senjutsu rasenshuriken...
As a finishing touch Xander spiked his hair with the little sample tube of hair gel, unaware that this was actually the last of Ethan's potion used to treat the costumes with.
Ethan grinned as he felt his spell activate, moments before a wave of chaos magic burst forth from the Janus bust.
The wave of chaos magic spread through the town, transforming those targeted by the spell right up until it encountered Xander. Between the extra helping of chaos potion, his nature as chaos nexus and the hybrid status of his character, Xander's transformation went far deeper than the mostly illusionary transformation of the others.
Xander transformed on a genetic level, truly becoming Uzumaki Arashi