It can still improve?

"Whooooooooo! Yes, we did it!"

The cheers of two teenage gir, cough, two very masculine, strong men, came from within a room on the ship.

It had been five days since they started attempting to find the right rune combination. They tried thousands of new, never seen before runes, where hundreds were engraved onto Merling for testing. He was originally very bitter regarding this. But all those feelings went out the window the second they succeeded. 

"It really worked! It seems to be a temporary rune, it dissipates after using it once, but Samuel, we really managed to do something everyone thought to be impossible. Although the rune only consists of one use, it equals one full-power attack that requires minimal qi. If we engrave enough of them on our bodies, we'll have countless trump cards"

Merling was beyond excited thinking about the prospects of this new method of theirs. However, his excitement was but a mere fraction of what Samuel was feeling. 'Since the runes are one time use, and I'm never going to stop using mine, doesn't that mean it will last forever. It's also self sufficient since it is the gateway of energy into the time sphere, meaning it is the first receiver of my reformed qi. Hell yeah, I'm basically invincible now!'

"Teacher, I'll go back to my room trying this for myself since we have the method of doing it. How long do I have before we reach Stargate Port"

"Originally we would arrive in five days, but since we deviated from our original course, it'll take another five days"

"Okay. I'll be preoccupied with this for the remainder of the voyage. You understand the need for undisturbed focus, so don't interrupt me unless necessary"

As he finished speaking, Samuel left for his room, where he started an intense session of brute force creation inside his time sphere. 

"Not this. Not this. Not this. Not this. maybe this?"

Samuel continued to try and fail as time passed. However not being able to see the rune in its entirety proved damaging to his method. He could only see certain parts and lines, forming something that could barely be qualified to be a pattern. 

"The only way I won't have to spend thousands of years here to find the correct rune, is if what I can see of the rune is what allows me entrance. I have to try this first then, if it doesn't work, I will be VERY upset"

However, his fears were unnecessary, as his first attempt at drawing the incomplete rune proved successful.

"Just like that? This is too easy, isn't it?"

And it was easy indeed. Choosing to finish engraving the rune as quickly as he could, he uttered 'gowla' and started prepping the 'ink'. He cut a very slight slit on his wrist, allowing blood to pour out in controlled amounts. He then covered it in his spiritual qi that was leaking out of the time sphere. He proceeded to use the carving knife given to him by Merling to carve out the most complex rune the world has ever seen. One. Straight. Line. That's right, one straight line standing between the eyes, starting from the Yin Tang acupoint up to into his forehead, but not much. It basically looked like a third eye, only golden in color. Unlike Merling, who's runes were the color of blood, from the ink, his was gold. A pure, glowing golden slit like rune in between his eyes. It looked very flashy, but few people in the Shattered Realm could ever even recognize this thing as a rune, nor its invincible effect. 

When he finished drawing the rune, a sort of enhancement of the rune on his soul seemed to appear. The rune seemed to become more clear, as well as the suction speed it has on spiritual qi and the consequent reinforcement of his body increased more than tenfold.

"Does this mean my rune talent will continue to improve as I improve my understanding of it, or what it symbolizes?"