Sarutobi was surprised, what else could he say about what they did? He never expected the instructors to grow a small piece of a brain but they did and what was he to do now? Why is Sarutobi asking himself these questions?
Simple, You see Naruto Uzumaki had graduated from the academy at 10, on his first attempt, as the instructors planned for him to die on a mission from his lack of training but now who to place him with? The teams had already been decided.
Kakashi was not an option as the Council would be so... troublesome if he placed him with Kakashi. So who to place him with? Who could bring out Naruto's potential?
He looked through the files on all of his shinobi and then filtered out who he could give Uzumaki to. It couldn't be one of the clans as it technically gave one more Clan more power than the others.
It couldn't be any of the usual Jounin choices as they were testing the teams, so who was loyal and wouldn't treat him unfairly because of what he holds, maybe one of his Anbu?
But that left the interesting question of who had enough political and normal power in the Village to protect the boy from those inside and outside the village who wished him harm.
And then he saw a file, one that he wouldn't usually use but he was desperate enough to allow this. The photo showed a brown-haired man dressed in black clothing and gloves with a grey flak jacket and arm guards covering it, on his right arm, there were bandages. Over that, he wore a white cloak with the hood up. On his face was a porcelain mask with a dog motif with pointed ears. The mask had three large strikes with two on each cheek and one on its forehead.
Many would think this is just an Anbu Captain but that was further from the truth, he was the current Commander of the Anbu Black Ops, a legendary Assassin and the Fourth most powerful and skillful Shinobi in the village with a lot of political power.
'He is analytical and intelligent, he knows Naruto's history as he has been an Anbu since the time of the Fourth Hokage, plus the Council can't order him around, he's perfect,' thought Sarutobi but decided to see the negatives too, 'He might kill Naruto's boisterous attitude, but is that really a negative? Nah, but he might Naruto into an assassin, but he would live, he wouldn't be an emotionless weapon, so an assassin is good enough.'
"Please call the Anbu Commander here," said Sarutobi as one of his Anbu rushed off, to complete his leader's order. Minutes later the third most powerful Shinobi in the village behind him and Kakashi was in the room.
He bowed to the Third Hokage as Sarutobi motioned for him to stand.
"You called for me, Lord Hokage?" asked the Commander.
"Yes, I have decided to give you an apprentice," said Sarutobi, smoking his pipe.
"Why me, my Lord?" asked the Commander, he would accept any duty the Lord Hokage gave him.
"Simple you are the only one I can trust to teach him to the fullest of his abilities," said Sarutobi.
"Naruto Uzumaki," said Sarutobi, and suddenly the Anbu Commander understood.
"What may I train him in?" asked the Anbu Commander.
"Whatever you wish," said Sarutobi as he handed the Commander Naruto's file. The Commander was shocked at how bad they described him at everything yet the boy could prank even the most elite of Shinobi, it was honestly hilarious how inconsistent wasit is.
AN: this is a story using what the Narutopedia wiki says is the Anbu Commander or the presumed Anbu Commander, he has been seen in episodes such as during the Konoha crush arc flashback to Orochimaru. He was also there when Danzo was chosen as the sixth Hokage