Kakashi
Kakashi is 14 when his sensei dies, when he is barred from raising his little brother in everything but blood. He is 15 and so entrenched in Hound that Kakashi is just a tiny voice in his head that cries for dead pack and Hound can only sneer as he wipes blood from his Tanto. They have no use for a pack, they have a mission. They meet the baby tree who lives in the roots. They may not need a pack, but the sapling does. Hound and Tiger become the beginnings of what will one day become the legendary Team Ro.
At Twenty-Four the Man who is Mostly Hound but who was once also Kakashi has a pack full of puppies. Deer is the only one that isn't a puppy. But she also is on the sidelines of the pack. He never wanted a pack, and she doesn’t need one like the others do. They are both fine with this arrangement. She can keep up, that's all that's needed.
It is Kakashi at 26 who witnessed a boy who is pack only in bonds long gone graduate from the academy. Something in him mourns that he never fought harder to raise the boy. Another part rages that the only thing left to raise a baby was a 14 year old mourning everything he loved and even that was denied. But Hound is anything but disloyal. And even he knows how harshly weapons are forged.
He’s just happy no one wants him to teach the kid, he’d simply mess that up. As much as Kakashi longed for the pack he was never as good as Hound at protecting the Pack.
His puppies will look after the boy anyways. Even if it's just because of the others on the team.