In the next six months, Kakashi masters fifteen personas and changes between them like he changes clothes. With every mission he goes with Snake or another ANBU of the infiltration team, he adds another character to his repertoire.
The ANBU captain brings Kakashi down to T&I to try out his more aggressive personas and to work on some interrogation tactics both with and without the Sharingan. After all, knowing how to see through (tear down) others' lies and pretenses is just as important as knowing how to construct your own.
Rin excuses herself during these sessions and Sakumo doesn't stay after the first time Kakashi takes a kunai to a man's eye with a ecstatic smile on his face. ("Make them believe you'd relish any opportunity to hurt them.") Instead, they go puppy watching at the Inuzuka compound with Kagami and Kara, and try not to think too much.
But of all the personas he has developed, Kakashi's favourite is Sociable Kakashi. The ritual he uses to slip into character is simple: first, the jounin uniform, article by article; second, the hitai-ate slanted over the Sharingan; third, a slouch with his hands in his pockets; fourth, a crinkle-eyed smile in the mirror; and lastly, an intractable lateness.
Sociable Kakashi can go out to eat dango with Gai, Kurenai and Asuma. Sociable Kakashi can laugh at their jokes. Sociable Kakashi can go to the public onsen with only a handkerchief over his face.
He's connected, friendly, likeable. He is Kakashi and he isn't. (Not really.)
Sakumo wonders who he does it for — his friends or himself? The gentle happiness that sometimes softens his gaze gives Sakumo hope. Maybe this is the ideal version of himself that Kakashi had always wanted but couldn't achieve innately. Maybe that's why he takes this persona out for a stroll so often.
But there are other moments too, when Kakashi is sitting amongst friends yet still caught in some lonely, distant orbit. Sometimes, he looks at them as if they're a comedy he doesn't find funny, his uncovered eye impossibly dark and jaded. Other times, he just looks young and frightened, afraid of getting close for fear of having them torn away again. The second anyone glances over though, he'll be smiling again at something or other.
As Sakumo had feared the moment Snake made her offer to take Kakashi as her protégé, Sakumo finds himself second-guessing the genuineness of Kakashi's responses. The spectre of doubt is... extremely discomfiting. The best lies are those which are half-true and Kakashi's personas all contain genuine pieces of himself woven into a greater tapestry of falsehoods. Kakashi's thoughts are privy to no-one but himself and trying to pick out the real from the fake is becoming increasingly difficult.
The cenotaph becomes a place of truth. There are no pretenses needed when Kakashi stands before the dead, the sweet scent of incense in the air. But this self-flagellating, burdened Kakashi is a shard of honesty that Sakumo knows all too well.
Eventually, Snake passes down her special Henge to Kakashi. It is a complex mass of seals that she had inherited from her own sensei, who had been an Uzumaki. Since the seals work on the chakra pathways to support the Henge's stability, they are supervised by several med-nin, a Hyuuga, and a very enthusiastic, newly pregnant Kushina. She wastes no time smacking Kakashi for asking if the embryo is made of ramen.
Snake coerces everyone into signing confidentiality contracts, except Kakashi himself, of course, and Kushina out of respect for her Uzumaki roots. The process itself requires a litre of ink made from Kakashi's blood, a ten metre diameter circle of white vinyl flooring, too-cold air-conditioning and one Kakashi who can't stop sneaking peeks at the symbols surrounding him. "Stay still!" Kushina roars, and Kakashi flops back onto the ground immediately, blinking innocently.
A surge of chakra and a gritting of teeth later, the seals take their final form: five overlapping Uzumaki spirals surrounded by a ring of symbols, tucked under the wing of Kakashi's left shoulder blade.
With his cheek pressed against the floor, Kakashi smiles. (It's probably real.)