A Navi Stage was dependent on two things primarily.
The physical capacity of a person to collect the Navi and the spiritual capacity of the person to use the Navi. The body and the mind together needed to improve in order for the person to move up in the Navi Stage.
It was very commonly believed that the process of going up a Navi Stage was what led to a person’s Navi quality improving. However, the truth was that improving one’s Navi quality was the defining factor that moved them up a Navi Stage.
And the quality of the Navi depended entirely on the person’s body and mind.
To improve both, all one had to do was continue gathering Navi and using it through their body and mind.
In the case of a Warrior, who did not have a Sea of Navi, they gathered Navi into their body and made use of it constantly. That very reason was enough for a Warrior to have constantly improved their body with their Navi.
As a result, they had to improve their Spirit to further move along in their Navi Stage. Since Warriors could only gather so much Navi into their body, they could only use weaker spells in order to not burden themselves with how much they needed to improve their Spirit.
The process of gathering Navi into their physical body, instead of a specific organ in their body, also caused the quality of Navi in a Warrior to generally be worse than that of a Sorcerer.
In the case of a Sorcerer, who always kept their Navi in their Sea of Navi, the only thing they needed to improve physically was the organ that was the Sea of Navi. Each time they absorbed and used Navi, they would slowly improve their Sea.
Unlike a Warrior, a Sorcerer needed a slightly longer time to improve their Sea since they never constantly made use of it. However, this requirement rarely mattered to a Sorcerer since they always improved it by merely using spell after spell.
So long as the Sorcerer didn’t directly use their spell using a Navi Stone, bypassing the Sea, they would always end up improving their Sea far earlier than their Spirit.
As a result, for a Sorcerer, the bottleneck usually ended up becoming their Spirit as well. And the more spells they learned, the tighter the bottleneck. If one were to get greedy, it could take them years to improve.
In a way, both Sorcerers and Warriors had the same bottleneck. As long as they improved their Spirit, their body would be ready to continue. However, for a Sorcerer, the bottleneck was much greater because the type of spells they learned and the number of spells they learned were usually much higher.
That difference was compensated by the fact that the quality of Navi within a Sorcerer was almost always of a higher quality than that of a Warrior, allowing them to use incredible spells that a Warrior of the same Navi Stage never could.
In the case of Jax, however, things were slightly different. Because of his restriction, he could only ever use a single spell. And the lack of restriction on how many times he could use that spell made it so that he usually ended up improving his Spirit much faster than even his Sea of Navi.
That ended up making his Sea of Navi the sole reason for his bottleneck, which he could easily improve so long as he constantly absorbed and used his Navi. This was the same bottleneck that was negligible to other Sorcerers, after all.
However, it now caused him an issue he hadn’t seen coming.
Because his bottlenecks were so much less than other Sorcerers and Warriors, he would easily move on to the higher Navi Stage. As he improved, so would his Spirit.
And as his Spirit improved, so would the requirement for his spells.
Jax had managed to unlock the Poison element of the Divine Threads with just two Poison Opal Stones. However, if he were to break through to the 3-Star Opal Stage, it was likely that he would require at least three Elemental Opal Stones to unlock the next one. And as he improved, he would need more and more.
Finding a boss monster when thousands of other individuals also searched for it made things a lot harder. Jax had gotten lucky finding the Mushroom Boss, but finding another boss would take him a long time.
"In the first place, not all boss monsters are guaranteed to have Elemental Navi Stones," Gemma said. "You’ve read the book on monsters and bosses. Most are, in fact, Non-Elemental Stones."
Jax nodded. "That does make things difficult. They don’t sell Elemental Opal Stones, do they?"
"They do, but not in the 10th Carriage," Gemma said. "Anyone with a helper would know the value of an Elemental Opal Stone. They are terribly useful in both potions, runes, and employing large-scale magic circles, so they end up costing a lot."
"Everyone in the 10th Carriage knows this fact, so they keep their stones until they go to the next Carriage, where they can get a better value from it. So you likely won’t get it in this Carriage."
Jax slowly nodded. "Then I must head to the next Carriage as soon as possible. Which means I’ll have to improve my Navi Stage as fast as I can."
He felt at his Sea, which was filling with the Poison Navi, and began using it once again. Both the act of absorbing and using Navi improved his Sea together, making him even faster.
The new skill he had learned let him be twice as fast as any other person out there.
The threads spooled next to Jax, which wouldn’t last there for long. Because the threads were created using Poison Navi, they had a Poison Element applied to them without his approval.
And because it had an element in it, all threads that he created would disappear in just two hours.
That didn’t matter to him at that moment. All that mattered was that he reached the 3-Star Opal Stage as quickly as he could.