Compared to the Byakugan, Sharingan, or even the Rinnegan, the "Mystic Eyes of Death Perception" held by Hagoromo were undoubtedly a more fundamental power, or rather, their very concepts were entirely different.
The Straight Tomoe Sharingan was "straight," and the Mystic Eyes of Death Perception were also "straight" (direct), but the two shared absolutely no similarities. The Straight Tomoe excelled in tracking and insight, with its visual prowess leaning more toward physical attacks, while its genjutsu capabilities were slightly weaker.
Meanwhile, Death Perception, as its name implied, was simply the ability to look directly at "death."
As long as there is a beginning, there must be an end, thereby allowing everything to be reduced to nothingness. According to the laws of all things, cause precedes effect. But within the vision of Death Perception, it was different—or rather, reversed. Decapitation leads to death, but conversely, without the act of decapitation, the resulting death shouldn't occur. First comes the cause of being severed, then the effect of death. However, the Mystic Eyes of Death Perception did the exact opposite: they first induced the effect of death, which then generated the cause of being severed.
Connecting cause and effect were those "Lines of Death"—in extreme terms, the atmosphere, will, language, space, time, and so on, could all be classified as existences these eyes could obliterate. In fact, these Mystic Eyes had indeed obliterated a predestined "future," causing an event that was absolutely certain to happen to vanish.
However, this placed incredibly high demands on the user. In reality, it was exceedingly difficult to see the Lines of Death on many conceptual things. For example, a predetermined future could be erased, but what about a future filled with infinite possibilities and unknowns?
Such a feat was likely something Hagoromo would never be able to achieve.
According to the activation conditions of his eyes, the first awakening required a near-death state, and subsequent uses likewise required some sort of dire predicament. Therefore, this "S-rank" ability—rather than calling it an overpowered skill that could only be activated near death—was better described as a desperate emergency measure to be used when he was about to die.
Regardless, this power was the highest caliber ability on a fundamental level. So, compared to the idiot-proof, plug-and-play Electromaster ability, its usage relied entirely on Hagoromo groping his way forward himself. And compared to the most orthodox users who used it as easily as breathing, using it always placed a certain mental burden on him.
Although not exactly the same, if forced to make a comparison, it was somewhat similar to the Sharingan in Kakashi's possession.
Instead of feeling like an S, it actually felt a bit M. This situation made Hagoromo slightly frustrated, but he quickly understood that this was only natural.
If he could easily push the eyes' power to their absolute limit, then this world would just become a trivial grinding dungeon. After all, theoretically, whether Kaguya or Saitama appeared before him, he could poke them to death with a single finger...
Therefore, such an unreasonably convenient situation didn't occur. Ryougi's Death Perception could be toggled freely, and Tohno's Death Perception seemingly couldn't be turned off, while Hagoromo's... fell into the category of being rather difficult to turn on.
His Visual Prowess was extremely polarizing. But considering its activation conditions, Hagoromo had no choice but to classify this power into the unconventionalf system.
So, after all was said and done, why couldn't they have just given him a Death Note to begin with?
Well, complaints aside, what Hagoromo truly needed these eyes for was killing things that couldn't normally be killed. That alone was enough.
He naturally needed to explore how to use the eyes, but more importantly, his conventional combat capabilities also needed strengthening, which was why he occasionally went to the Shikkotsu Forest.
Leaving aside his Electromaster ability—as leveling it up further was basically impossible, and at most he could only refine its precise applications—when it came to ninjas and ninjutsu, there were still many things Hagoromo could improve.
Aside from skillful ways of using his abilities, the super-massive Railgun was essentially Hagoromo's most lethal technique. But in future uses, he absolutely would not fire something like the Rashomon gate again.
Just picking an appropriately sized object to fire would do. The cost of launching Rashomon was far too great.
Though... he would probably never encounter such a desperate situation again.
Setting aside these unique powers of his, as a ninja, Hagoromo's biggest problem was his stamina... Saying he had low HP was one thing—most ninjas were glass cannons anyway. But even among glass cannons, there were differences. In terms of chakra reserves, other glass cannons had plenty of MP, but Hagoromo... was still trash.
Although he wasn't fundamentally the kind of ninja who relied on chakra to fight, if he could strengthen it, he might as well.
How to solve this problem? Hagoromo already had an idea.
At this point in time, the Third Hokage didn't seem to have any intention of sending him back to the battlefield. As for the missing persons investigation he was currently on, he was completely phoning it in. He couldn't lend a hand in taking care of the twins either. So, he could make time to go to the Shikkotsu Forest and research those things he had been interested in for a long time.
Purely in terms of territorial scope, although Hagoromo had never been to the other two sacred grounds with Senjutsu inheritances, intuitively, he felt Shikkotsu Forest should be the most expansive one.
The atmosphere was hot and humid, veiled in dense water vapor. Although the terrain fluctuated, it was generally flat. Towering broadleaf forests blocked out the sky, turning the entire space into a windless zone.
Truthfully, being in this space was not comfortable at all. All year round, it felt like 2:00 PM in the hottest, most humid tropical rainforest.
Hagoromo used Reverse Summoning to arrive directly at Shikkotsu Forest. In reality, this place was only "damp" (Shitsu); he didn't see any "bones" (Kotsu). But looking out, he could see a milky-white mountain mass in the distance... That wasn't a mountain; it was Katsuyu's main body. It was the highest peak in this entire region.
If someone could summon the entirety of Katsuyu to the outside world all at once, Manda and Gamabunta probably wouldn't even stand a chance.
Katsuyu naturally sensed Hagoromo's arrival, but it didn't move toward him. Moving such a colossal body was extremely inconvenient, and it was impossible for it to come all the way over here.
At most, it would just send a divided clone to move around.
As for the occasional roars echoing through the area, Hagoromo recognized them; that was the little dog he kept.
These summoning beasts undoubtedly stood at the apex of this ecological zone, eating whatever they pleased.
But what Hagoromo came to do today had nothing to do with the summoning beasts... Following the stone steps beneath his feet, he walked step by step in the direction they extended.
Every thirty meters or so, a mottled vermilion torii gate stood above the stone path. In the extreme distance beyond the line of sight, there was a rather grand cluster of man-made structures, painted in the same color.
On both sides of the stone path, one could see ferocious, demon-faced iron gates. Those were the Rashomon.
As for exactly how many gates there were, Hagoromo had never counted. Anyway, if someone had an absurdly massive amount of chakra and wasn't afraid of making redundant defenses, they could absolutely summon fifty layers at once.
Although located in the same place, Rashomon and Katsuyu did not belong to the same summoning system. Hagoromo had learned this jutsu from the Scroll of Seals. The Rashomon gates he used were all summoned from within the Shikkotsu Forest.
These man-made objects, including the architecture, were highly likely related to the Senju clan. But whether that was truly the case or not, Hagoromo didn't know, nor did he have much interest in finding out.
In terms of power systems, the might displayed when the First Hokage Hashirama Senju's Senjutsu combined with his Wood Style was what was truly powerful. Senjutsu stripped of Wood Style didn't have such obvious suppressive dominance.
And Wood Style stripped of Senjutsu was probably around the level of the Reanimated First Hokage fighting the Third Hokage.
Only when Senjutsu and Wood Style were combined was the First Hokage the true First Hokage... Hashirama Senju had Hashirama Senju's way of being powerful, and Hagoromo had Hagoromo's way of being powerful.
Stepping past the final stair, a square stone plaza lay beneath his feet.
Unlike the densely forested other areas, because the elevation was slightly higher here, it appeared relatively open.
And appearing before Hagoromo's eyes at this moment were several wooden towers brimming with a peculiar energy.