Chapter 43:
Danzo had just established the Root division and was eager to inject fresh blood into it.
That's when he noticed Orochimaru.
Just like he would later notice Kakashi.
Why did Danzo focus on them? Because Orochimaru and Kakashi shared two critical traits: unparalleled ninja talent and a lurking darkness deep within.
In Danzo's mind, such talents naturally belonged in his department.
Letting them grow outside his control would be a waste of potential.
However, at this stage, because the foundation of the Root was still unstable, Danzo was forced to obey the orders of the Third Hokage, Hiruzen.
But as for Orochimaru, he had already taken note of Danzo.
To the general public, Danzo was seen as a man of immense ambition selfish, power-hungry, and utterly ruthless in his desire to ascend to the position of Hokage. A dangerous figure, no doubt.