Chojusen placed his three unconscious comrades in a little earthen house he made out of his Elemental Creation Skill. He healed them with his Water Healing and Yang Rebirth Skill. Sasuke was the first to show signs of awakening, so Chojusen decided to leave when he saw Sasuke open his eyes and get up.
Before teleporting back to the tower in the center of the forest, Chojusen was shocked to see that Sasuke had a two tomoe stage Sharingan. Sasuke had awakened a one tomoe Sharingan the day before the exams after almost dying while attempting to pull of his Kirin attack. Seeing his friend pass through the stages of a dojutsu like they were nothing special, made even Chojusen sign in vexation.
Chojusen teleported back to the tower and began to plan out his next course of action. He wouldn't help Naruto's team much aside from ensuring their safety, as he had come to understand Guy's teachings about letting the people he cared about grow up.
Back in the tower, Chojusen began a world wide scan to see where Orochimaru was hiding. The reason he didn't pick up the Orochimaru's energy signature earlier was two fold. First of all, Chojusen didn't have his teleportation sensing constantly active; that would overload his mind and he would feel bad for snooping on people's "private affairs." Secondly, Orochimaru only had a bit of his energy signature released when he unleashed a large scale attack; if it had been leaking, during his whole fight with Naruto and company, Chojusen would without a doubt, easily have intercepted him before he could escape.
It was at this moment that he realized he was missing a detection skill. He could use his teleportation sensing to scan the world for Orochimaru's energy signature. However, if the snake-man used even a worthless C or B Rank concealing skill, he could hide his aura and energy signature from escaping.
Since Orochimaru had infiltrated the Hidden Leaf, it was safe to assume that he would at least try to hide his aura. If he didn't, his teacher, Hiruzen Sarutobi, the Third Hokage, and literally anyone that ever knew him somewhat intimately, could potentially discover him. Of course, he would also disguise his physical appearance, for obvious reasons.
Chojusen didn't want to let a threat as dangerous as Orochimaru run amok, so he asked the system if he could buy a detection skill.
[You want a detection skill? Well, if you want the best detection skill in the multiverse, you're going to have to cough up 100,000 shop points. Or I could give you one that can be trained up to the Immortal Level for just 1,000 points.]
"Wait, why does a skill on the same level as the Omniseal Unlock cost ten times as much?"
[Everything aside from the strongest skills in the multiverse have a fixed price. However, for those skills that are the best of the best, my creator, the creator of the system, made it so that the price would increase by ten times every time you wish to buy another end-game tier skill.]
"Whatever. Can I get a skill with my current shop points that will let me detect Orochimaru?"
[Mhmm… Honestly, I would be embarrassed to have you as my host if you had worthless skills with no future… How about this, for 400 shop points, I will give you the all the foundational knowledge for yin, yang, chaos, and time that is required to master the greatest detection skill in existence. If I can't convince you… you can buy a detection skill that can be trained up to the SSS Rank for 100 shop points.]
"Mhmm? A choice again? Let's see now. If I remember correctly the last time you gave me a choice, I went through something so traumatic, my eyes improved by a stage..."
Chojusen could hear the system start whistling as if to try and pretend it hadn't heard him just now. Ignoring the system, Chojusen though very hard about the choices he was given. He didn't have a quick way to earn more shop points, so he could only choose between buying the SSS Rank skill or the foundational knowledge.
Right now, he wasn't in an do-or-die state, so buying the foundational knowledge was the most reasonable choice. Chojusen asked the system one question before deciding his choice. "Will you tell me what I have to do with the foundational information to reach the standard for the best detection skill, or will I have to figure it out myself?"
[Actually, you don't even need to buy the skill for me to tell you how you could eventually achieve recreating the greatest detection skill. I will just tell you right now. To recreate the detection skill, you would need to fuse at least four types of high tier energy to use a detection skill.]
"High tier energy?"
[Energy tiers are determined by the universe you are in and their world laws. In the current universe, low tiers of energy are fire, water, wind, etc. and high tiers of energy are space, time, yin, etc. The reason I chose to give you the foundational knowledge for yin, yang, time, and chaos energies is that they are universally considered to be high tier energies.]
Chojusen bought the foundational knowledge and immediately got to work. He entered his personal dimension and dispelled all of his clones, before making a new set of clones that started to work on developing detection techniques with the knowledge he had just bought.
It didn't take long for Chojusen to hear a string of prompts from the system. The long list of skill improvement and skill creation from the system ended with one final prompt.
[Host has fused the two skills, Time Divination and Yin-Yang Detection, to create the skill: Origin Detection
Origin Detection (DI | 0/100): The user uses yin, yang, time, and chaos law principles to peer into the essence of living things. Current Effect: Anything the user recognizes within their range of detection will be identified without a flaw, so long as the target(s) have a weaker understanding of any of the four types of energy used to activate this technique.]
At this point Chojusen was confused. Was this not the ultimate detection skill in the universe? The system offered to give him the best detection skill for 100,000 shop points, but he had recreated that same skill after only spending 400 points and a bit of time?
The system could read Chojusen's subconscious thoughts so it said [The skill you created is not the best detection skill in existence; though it is pretty close.]
"What would make my detection skill any better than it currently is?"
[Well aside from improving it to the full Immortal Rank, it could only match the best detection skill in the universe if it were able to identify a person you didn't recognize. You see, for your skill to work, you already need to know who you're looking for. Also, for a target to bypass your detection skill, all they need to do is have a more profound insights into any one of the four energy types. For the ultimate detection skill, a target could only evade detection by mastering all four energy types to a higher degree than you.]
Chojusen had to admit, having a skill that would let him identify anything and everything he could sense would definitely be the ultimate detection skill. But, he could definitely make due with the insane Origin Detection Skill he had created.
Chojusen left his personal dimension and used his new Origin Detection Skill in conjunction with his teleportation sensing. To Chojusen's disgust, he found that Orochimaru's "essence" was present in at least several hundred people; even his friend Sasuke was not spared. Across the whole world, Chojusen found that people with a certain three tomoe mark, had a bit Orochimaru's essence within themselves; Sasuke and Anko being two that he knew.
Chojusen scrolled through the compendium of seals, and found that the three tomoe mark was actually known as a Cursed Seal of Heaven. The Cursed Seal of Heaven is absurdly powerful when used optimally. Aside from allowing himself to live on as a piece of essence when his main body died, if mastered to the SSS Rank, Orochimaru could have actually been using the seal to steal the genetic data of all the people he cursed.
Fortunately, his proficiency with the curse mark was just at SS Rank; Chojusen could break it with his current proficiency in the Omniseal Unlock.
Before Chojusen could even send his clones to eliminate all of Orochimaru's presence in the world, he realized that Orochimaru's current true body, the one that had the most of his essence, was in fact working in the Chunin Exams as a supervisor. It would be best if he eliminated the main body first, and then destroyed the remaining seeds.
Chojusen walked to Minato's room. As the current Hokage, he had a role in supervising the Chunin Exams, so he also had a room in the tower. Once Chojusen was allowed entry into the Hokage's room, he told Minato about Orochimaru and how he had infiltrated the Chunin Exams.