While Tobias remained lost in the dark without a clear method to save Kara, Rin studied within a quiet mountain cave in Hell Difficulty’s Second Zone.

Specifically, Rin was attempting to study the laws of the time and incorporate them into her bloodline to expand her superpower’s strength. This method of strengthening superpowers was commonly known in her homeworld.

The difficulty of such a feat was proportionately related to their current bloodline’s tier and the specific law the bloodline was related to. Needless to say, the stronger the bloodline, the more difficult the improvement.

Although the term ‘bloodline’ is used loosely as superpowers have little to do with blood. The exact mechanisms which involve the soul are pointless to explain as they work in a similar enough manner to how a physical bloodline would work.

Rin’s homeworld separated superpowered bloodlines into tiers. The weakest starting at tier-one reaching all the way to the strongest tenth-tier bloodline.

Tier-one bloodlines have little control of their strength, and come into existence mainly from random mutations or contact with strange objects.

Those in tier-two have conscious control over their powers.

Upon reaching the third-tier, people gain more in-depth control of their abilities and beyond that is mainly working on expanding the domain of their specific power with each increasing tier.

While powerful, Kara and Rin could only be considered tier-six. Their powers existed in a mostly controlled state... Rin’s was limited by save files and couldn’t reload to any moment in time, or choose to reload to future points. While Kara’s had limitations in terms of danger, the power behind forcing the entire universe to a specific outcome could be seen.

Those with superpower bloodlines easily reach the limits of their predecessors. A completely unfair advantage is that many descendants of bloodline powerhouses retain the tier of their predecessors. A tier-six bloodline can directly reach the sixth-tier upon awakening their power.

This advantage wasn’t perfect as those with higher-tiered bloodlines found it infinitely difficult to awaken their superpower to begin with and couldn’t use mana. Often times, unless those descendants awakened their superpower, they found themselves worse off than regular people.

It could be said that if Rin or Kara hadn’t been teleported to this universe and undergone the Redeemer’s process, they would’ve likely never awakened their powers. Directly awakening to a sixth-tier power while their bloodline was related to the laws of time, the difficulty of awakening by normal methods is infinitely higher than reaching divinity as a regular warrior.

The power of this bloodline can been seen perfectly through Rin’s ability to affected the entire universe while reversing time, effectively making her invincible amongst those at a similar level to her and even allowed her to attempt to leapfrogging those above her level.

However that also meant Rin needed to have an extremely strong understanding of the laws of time to upgrade her tier. Due to the unique nature of time and space, the laws related to them are considered one of the most difficult to comprehend and utilize.

This was called the so-called bloodline limit…

In fact, for those with superpowers, understanding the laws of the universe was only the perquisite to improving their bloodline. Truly upgrading their bloodline’s tier was extremely rare. Even with bloodlines operated by weaker laws, it was normal to go countless generations without a single person ever upgrading their bloodline.

After all, even if descendants had strong comprehension ability of the universe’s law, only a small number would awaken their bloodline… and even smaller number would be talented in laws relating to their bloodline.

The infrequency of bloodline improvement stems not only from the difficulty of awakening their bloodline and comprehending any relevant laws. Upgrading a bloodline’s tier wasn’t free of danger. A dangerous trial existed that preventing those who wished to advance tiers.

The devil’s tribulation was what people generally called it. A trial consisting of seven deadly sins; Sloth, Greed, Gluttony, Wrath, Envy, Pride, Lust.

Nobody knows why the devil’s tribulation exists, as there was no such trial for mages or warriors. It’s said the devil was jealous of those with a superpowered bloodlines and cursed them to go through additional trials if they wish to break through their limit. The difficulty of the trial being proportionately related with the bloodline’s tier.

Whether the trial is successful or fails, it is dangerous for those involved. Even success can result in significant soul injuries. Even if a genius with a bloodline comprehended the related laws, they might not dare to attempt the trial.

While superpowered bloodlines prevented utilization of magic, those geniuses could still become warriors and have the potential to reach deity-level in that manner. Those reaching deity-level could obtain immortality and power far above normal people.

The thankless task of risking their lives for the possibility of improving their bloodline limit was difficult for any genius to accept when it was unlikely their immediate descendants would awaken a power and it would potentially cause severe spiritual injuries, completely cut-off their chance of immortality in the future.

In fact, compared to superpowered bloodline, mages and warriors had far easier time reaching a higher-level. Warriors and mages required a far weaker understanding of the universe’s laws to upgrade than superpowers. Conversely, they less powerful than those with superpowered bloodlines.

Of course, this is only in a relative manner. Any deity-level could kill Rin millions of times over and would impossible for her to fight back. Similarly though, it would be impossible for an average deity-level to reverse time in a manner comparable to her.

Deity-level beings who have comprehended the laws of time would easily be able to notice and depending on their comprehension level, potentially track down the source and completely avoid the effects of her reversal.

That is to say, if Rin dared to be as blatant and whimsical in turning back time in her universe as she did here, a line of unhappy deities would have shown up at her doorstep. Even if they didn’t kill her, they would’ve stopped the blatant abuse of her ability.

Not that Rin was aware of this. How could she know the affairs of deity-level being? While her father had drilled knowledge of many topics into her that certainly didn’t apply to those hidden masters in the deity-level.

Fortunately or unfortunately for Rin, this universe had taken a more technical approach to magic. Instead of studying and comprehending the laws of the universe, they relied on formulas and principles of mana to explore the universe and create technological marvels.

That isn’t to say this universe is weaker than her homeworld, it simply took completely different path and specializes in different fields. This universe’s knowledge and information related to the laws of time are far weaker due to have little interaction with that field.

Before the existence of the corrupted mana and destruction of the majority of the system’s functions, Rin would’ve actually been discovered and tracked down due to her constant usage of the ability.

If the two universes actually fought a war when the intelligent races were at their peak, the winner would’ve been this universe with relatively certainly. The unity provided by the system and desire for survival in the early days of this universe’s existence resulted system where the intelligent races banded together very tightly. Even if that unity had been damaged to a lack of foreign enemies, the remaining system would have been propped back up in a time of war.

…But the appearance of corrupted mana causing unrest and internal fighting in this world weakened this universe enough that any battle would be in favor of her homeworld.

Of course, this is all under the hypothetical that the two universes went under an all out war. There was little need for such a battle in the first place. It was extremely difficult for the two universes to remotely interact with one another, nevermind fighting an all-out war.

Regardless, the result the decline of this universe meant that Rin can blatantly abuse her ability with little consequence. This universe no longer has the infrastructure to find the specific cause of time-anomalies, even if it still retains pockets that with the ability to detect and avoid them.

Not that any of that matters to Rin.

To be blunt, from Rin's perspective, her current ability is useless. It cannot save Kara or Tobias. Kara is trapped in a death-loop, and Tobias has completely vanished from history.

However, if her superpower grew stronger, then Rin had a chance of remedying both problems. The recovery ability of spiritual artifacts in this universe is better than her previous one. Rin has long since prepared the requisite artifacts for recovery afterward. As long as she is successful, Rin can recover from the tribulation and attempt to save them.

The warrior path is completely unacceptable to her as it means being unable to save either of them. While Rin is confident in reaching deity-level due to her superpower, there was little point as it wouldn’t help save either of them.

Only the laws of time can help in this matter.

If a tier-six bloodline is unsuccessful, then continue to tier-seven. If tier-seven isn’t enough, eight.

Failure only means the strength to succeed hasn’t been obtained yet. While Rin firmly believed this, ideals are beautiful and reality is cruel.

The law of time and space are not considered the most difficult laws to comprehend for nothing. Even with her ability to jump outside the web of time and observe how a scene will play out a million times from different perspectives, time is an elusive and enigmatic field to study.

Rin also needs to jump directly from comprehending the laws of time of the seven-tier without any of the feedback from previous tiers. In other words, there’s no way for her to verify whether her understanding of time is correct.

In a sense, such a feat is nigh-impossible. Without any way of verifying whether her understanding is correct, the idea of correctly comprehending the laws of time up to the seven-tier, without a mentor or teacher… tough to the extreme is a simply way of putting it.

The time it would take is unimaginable. Like a mountain, the further someone goes on the path the more difficult it becomes.

To continue climbing is difficult and even the first step isn’t easy… and without verification you cannot even be sure your climbing the right mountain. You might climb half-way to the top of the mountain only to discover your mountain’s peak doesn’t even reach the seventh-tier.

The idea of self-exploring the laws of time with no help, it would take an unimaginable amount of time.

However… if there’s something Rin is not lacking, it is time.

Rin already had a routine.

Practice for a year. Interact with Kara until her death. Repeat.

While Rin aged normally under these circumstances, her age reverted when utilizing her save/load making her effectively immortal. Continuing on this route, there was steady progress and no risk of failure due to a soul attack. She would eventually complete her task.

If Tobias heard of Rin’s plan, he would call it stupid to the extreme. There is no cleverness to it. There’s no thinking involved.

Simply put, Rin’s plan is to increase her strength to a level that the universe caves to her demands.

Who knows how many years, how many millennial that would take? Understanding the laws of the universe, specifically the law of time is too difficult. Even with fortuitous encounters and enlightenment, it’s impossible for a normal person to reach that height in their lifetime.

There couldn’t possibly be a stupider plan in existence. It’s simply brute forcing your way through the problem when it could clearly be solved through other means. Tobias had proved in his previous timeline that Kara could be saved through other means.

There’s a reason that Rin’s bloodline limit is the sixth-tier, it’s because advancing beyond that level is almost impossible in a person’s lifetime even for a peerless genius.

Regardless of the reality of the situation, Rin choose this arduous and dangerous path.

If her goal was only to save Kara, Rin might’ve taken another route… but as far as Rin was concerned, Tobias had disappeared entirely from history.

Specifically, Tobias had vanished after Rin had abandoned him as a partner causing her to feel responsible. While Rin only wanted his safety by distancing the two of them, he disappeared in a way she couldn’t reverse.

How could she accept that? She failed to protect him in an irreversible way and lead to her finally understood the truth. The safest place is by her side. At least, Rin would’ve learned what happened in person instead of vague recounts of the situation from Stanley afterward.