It was a tough decision.
[Decay Halo] was probably the most compatible with Ryu, but [Swallow Six Senses] was the most immediately useful and impactful to his battle strength. However, there was still [Soul Chain Battlefield] which was an excellent life saving measure no matter how you looked at it.
If someone was forced to battle one on one with Ryu's soul, his current inability to leap through Realms and challenge past his level would be mitigated somewhat. At the very least, someone would have to be at least three Realms or higher to truly threaten his life.
But there was also a glaring weakness of [Soul Chain Battlefield] as well.
It was one thing if you were in a one on one battle in an isolated location, but what if you were facing many enemies at once? [Soul Chain Battlefield] could only target a single person at one time, leaving your body completely vulnerable. So, it would go from a Secret Technique and life saving measure to useless pile of trash the moment you were facing two enemies you couldn't immediately defeat instead of one.
[Soul Chain Battlefield] wasn't the only one with issues either. But how could it be? It wasn't as though these were high class, flawless techniques. They might sound powerful in their descriptions, but so did the Common Grade techniques several levels down. It took a discerning eye to see through the tricks. After all, what technique creator would want you to think that what was usually their life's work was weak?
[Decay Halo]'s greatest weakness was the amount of time it took to work. It was a steady and continuous process, almost like a domain. It took time for the Spiritual Qi of an enemy to be slowly drained. One would have to fight at least a few hundred exchanges before some real, tangible effects began to take root.
Of course, to cultivators at this level, a few hundred exchanges wasn't even a few minutes. But the fact that you could levy that many strikes in the time frame was a glaring enough problem. If your enemy defeated you, or you defeated them, before the technique could take action, then wouldn't deploying it in the first place have been a waste of time?
Much like [Soul Chain Battlefield], [Decay Halo] was only useful in very specific use cases.
You wouldn't use it against someone weaker than you because it was a waste of time when you could just use your fist. You couldn't use it against someone stronger than you because you lost Spiritual Qi at the same rate as your enemy lost theirs. And, you obviously couldn't use it against someone who was your exact equal because then you'd both be incapacitated in the end. This meant that there was only one logical case that would be best suited.
If you were fighting an enemy who you were neck and neck, and you were certain the battle would go on for countless exchanges, AND this person happened to have a weaker soul than yourself, only then could you logically use this technique.
Unlike [Soul Chain Battlefield] though, [Decay Halo] could be used on multiple people at once, but it was almost never used like this either.
Why? Well the answer was obvious, if you were losing Spiritual Qi at the same rate as several people, wouldn't you become a mummified corpse before they felt a thing?
Then there was [Swallowing Six Senses]. This technique also allowed you to use it on multiple people, but there were glaring warnings against it.
The drain of the base technique was a big enough problem, but the main issue was the potential backlash.
The more people you cast this on, the heavier the burden on your Mental Realm, and the more likely it is that you could suffer backlash and in turn lose access to your own senses. With multiple people fighting back for control at the same time, very few would be able to handle such a struggle.
It only made it worse that while you were in such a tug of war, a lot of your mind and Focus Qi would be occupied, making it more difficult to end the battle quickly.
Ultimately, what Ryu learned about all of these weaknesses was that Soul Techniques were most effectively used as supporting skills, ones that would only be deployed when you had a group of people you trusted charging into battle with you.
Of course, beast companions was another possibility, although most of Ryu's own were sealed away right now. As for Necromancy, not so much unless you were a Summoner Necromancer who could trust your demons to control themselves.
All in all, these were steep waters, ones very difficult to trudge through.
But Ryu still made his decision, picking [Swallow Six Senses] after much deliberation.
In the end, the weaknesses of the other two were far too glaring. In truth, Ryu thought about going with [Decay Halo]. The techniques were about equivalent in drain and [Decay Halo] was more compatible with him, at least on the surface.
However, Ryu ultimately decided that [Swallow Six Senses] had the better effect of those he was looking for.
After picking out a Soul Technique, Ryu proceeded to drain the entirety of his accumulated merits by picking out seven Alchemy Techniques. Five of them were for the Pill Path while only just two were for the Potion Path. But this was expected considering the difference in rarity between the two.
The elder once again gave Ryu a ridiculous look. He found the situation so impossible to believe that he almost broke character and actually said something this time. But in the end, looking at Ryu's placid expression, he shook his head.
Ryu walked out with his gathered techniques and began making his way toward his living accommodations.
All Inner Disciples were afforded similar luxuries based on their ranks and Ryu planned on checking his own now for the first time.
However, when he made it to his living accommodations, his expression darkened.
Maybe he hadn't killed enough people yet.