Very spur of the moment angst stemming very much from an event directly related to Annwyd, actually.
She had asked him one time – he couldn't remember when – who the most painful in their team was. He hadn't known where that'd come from, random and disturbing as it was. There must have been something on his face, in his eye, his gaze, his posture; something somewhere to have elicited such a deeply scalding observation.
He'd wondered in what context she meant.
He'd wondered if it mattered.
His mouth had supposed it didn't.
Naruto, the teacher reborn, the cause of – so much - death; for being the demon that destroyed his village. For being Obito. Because he was them all, because that made Naruto.
Sasuke, for being me. Too much like me. For being me and so damned arrogant.
He'd seen it all coming so long ago – since the beginning; he'd failed to stop it.
You, for being Rin.
He'd grown quiet at that. She'd grown confused.
'I don't understand.'
He'd nodded. I wouldn't expect you to.
She'd looked offended, as if it'd been meant as a slight on her intelligence.
But she'd said nothing, only maintained that state of thinking for some moment before letting it go. She was ever-understanding.
'It hurts you to be around us.'
Really was too much like Rin.
Yes. It does.
But sometimes it is specifically because it hurts so good that you stay.
The quotes are placed as are for a reason. That reason being the displacement Kakashi feels towards most things. The quoted lines are what snap him back to reality, however briefly, before he once again drowns in the past and his thoughts.
So is intended, anyway.
On Naruto and the 'Yondaime reborn' business: my theory is that the Yondaime sealed the Fox within himself. Seeing how he was to have 'died', I believe his disappearance is due to having sacrificed his life to contain the demon within himself. However, because it is a demon and therefore awesomely strong, a human body is not strong enough. By writing his own life into the sealing jutsu, he'd included it as 'payment' to create the vessel needed and merged both himself and the Fox into one, creating 'Naruto'. In the end, there is no Yondaime, no Fox, only the boy who is both combined. If Naruto dies, Fox goes with it.