Created by the Second Hokage, ANBU is the department within the village in charge of carrying out secret tasks and they only answer to the Hokage.
These tasks can range from tracking and assassinating deserter or enemy ninjas, interrogation tasks, to simple surveillance of important places or areas.
If you consider that a village has many ninjas to complete many tasks, then what need is there for the existence of ANBU?
After all, the Hokage could order the Leaf Village ninjas to perform the kind of tasks that ANBU commonly carry out.
The official reason is that these types of tasks require certain skills, and ANBU is responsible for training its ninjas specifically for these tasks.
But what everyone knows, yet no one mentions, is that ANBU is also a weapon of the Hokage. A resource to maintain his control over the village.
After all, a village is made up of countless ninjas, and many of them are from family clans.
Therefore, there were conflicts of interest.
The Second Hokage was aware of this conflict of interest and created ANBU to answer only to him.
In Tobirama Senju's thinking, future Hokages will be able to keep troublesome clans in check with the help of ANBU.
But what Tobirama didn't say at the time was that he created ANBU to carry out problematic missions—those that required absolute secrecy.
When the Leaf Village was created, the Daimyo gave his permission with certain conditions.
One of them was the prohibition of certain types of missions such as assassination.
Unless they were criminals, the Leaf Village could not accept missions to assassinate people from the Land of Fire.
But this was not done because the Daimyo was concerned about his subjects.
But to ensure the future well-being of him and his family.
During the era of warring clans, many assassinations of nobles and Daimyo occurred, being part of the regular chaos of that time.
Although the Daimyo and the nobles of those times were furious, they were defenseless against the ninjas.
Although they had numerous samurai armies, the skills of ninjas are unpredictable and they could easily retreat after an assassination.
And without catching the killer, it was difficult to punish him or the ninja clan he belonged to.
There were thousands of ninjas within his country, and it would be like looking for a needle in a haystack.
Therefore, the Daimyo at that time took advantage of the gathering of so many ninja clans to try to control them.
After all, a lot of money was needed to build a ninja village and fund its annual expenses.
The Daimyo wasn't going to spend so much money to build a small country within his own that could rebel in the future.
In addition to the presence of Senju Hashirama and Madara Uchiha at that time, the Daimyo accepted the founding of the ninja village to decrease the number of ninjas who might come after his head.
The Leaf Village got their money for its creation, and the nobles of the Land of Fire had fewer worries about being killed.
But in the long run, it was the nobles who smiled in the end.
After all, assassination missions were the best paid and were the biggest source of income for a ninja clan.
The nobles not only managed to keep the Leaf ninjas from going after their heads, officially, but now they also had a lot of influence over them through annual funding for the Leaf Village.
And since the Leaf Village had lost a good source of income, they had to keep the Daimyo and the nobles happy if they wanted to continue receiving money every year.
By the time Tobirama realized this, it was too late.
Although the missions that came to the Leaf Village were numerous, they were not enough to be profitable.
After securing a commission of thousands of missions a year, he couldn't even find a break-even point to maintain the village.
Tobirama found himself at a crossroads.
Although he needed money, he did not dare to accept assassination missions against nobles or important people within the land of fire, no matter how lucrative they were.
The village was very dependent on the annual money given by the Daimyo and could not simply remain at odds with the man for long.
The village's daily expenses are significant, and if they don't have money for a long time, the village will collapse.
Tobirama knew that he couldn't do it openly.
'But nobody knew,' the man thought.
After all, they are ninjas.
Solving their problems with violence is ingrained in the DNA of ninjas, and Tobirama was no exception.
As much of a genius as Tobirama was, his genius lay in jutsu and assassination, not in business and other ways to increase his village's income.
Therefore, when he encountered money problems, he did not think about forming an industry.
When he encountered money problems, Tobirama's first thought was to undertake missions.
Specifically in assassination missions, which were the most lucrative.
But since assassination missions were illegal, he needed the ninjas who carried out these missions to be as discreet and trustworthy as possible.
Instead of forming an industry to make money, the man instead thought of a way to carry out illegal assassination missions in secret.
Hence the existence of ANBU.
When a mission arose that was politically risky, ANBU was the one that took charge of carrying it out.
How much does it take to assassinate the Daimyo and try to rule the country?
Tobirama didn't think about doing that.
It would attract the attention of the rest of the world and could see a crusade from the rest of the countries and villages of the continent to destroy his Leaf Village.
Therefore, this was their solution to the lack of money.
ANBU missions reached the Hokage's desk after passing through a filter of the intelligence department, and he decided whether to accept the task or reject it.
Of course, there were missions that bypassed the intelligence department and quickly reached the hands of the village leader.
Like the one Hiruzen Sarutobi was reading in his hands right now.
The Daimyo did not often send out mission requests. And when he did, they usually involved a nobleman collaborating with a foreign country or the assassination of individuals he disliked.
If the mission was not problematic, the Hokage would usually accept it to keep the man happy.
Furthermore, the Daimyo paid well, so the Hokage usually had no reason to refuse his requests.
But this time he didn't accept the mission quickly.
The reason for this is the name Kozue Ichihara in the document.
Hiruzen recalled that some time ago his son sent an urgent message.
Since it was his son, his request was quickly executed by ANBU and reached him.
After reading the scroll, Hiruzen acted with urgency.
His son had encountered a dangerous stranger, so he sent an ANBU team to support him on his return.
Not only because he was his son and he wanted his safe return, but also because Asuma's students were the heirs of the most important clans that supported him.
At that moment he realized that it wasn't such a good idea to put those young men under his son's command.
Although it was a politically sound decision, it could end in disaster if those young people were harmed.
The work of a ninja is dangerous, but it's obvious there will be some resentment from these clans if an accident occurs.
But since it was too late to change his decision, he had to move on.
Hoping that the ANBU team would be able to support his son's team and prevent anything tragic from happening, the older man concentrated on the portrait on the scroll and what ANBU had on him in their current databases.
Although a thorough investigation is usually necessary, it wasn't required this time. ANBU already had information about the person in the portrait drawn by his son Asuma.
Kozue Ichihara, son of Tetsui Ichihara, the then head of the Ichihara family.
After learning that, Hiruzen sighed in relief because nothing bad should happen.
Although a confrontation almost occurred, in the end nothing happened and the Ichihara family should have no reason to continue the conflict.
Although he was surprised that a young man was strong enough to be considered dangerous by a Jonin like his son, there will always be geniuses, and he thought that Kozue Ichihara was one trained by the Ichihara family.
Families like this have their own secret forces, and since it was going through a power transition, it was logical that this young man would appear publicly.