Reaching inside the second shelter that was extremely close to the damaged spot on the mana vein, Jason was able to start investigating further without any hindrances.
First of all, he had to figure out what exactly the transmuted mana, the mana vein released, was.
At the same time, it was important to get to know all possible problems the damaged mana vein caused, and what kinds of problems existed, in the first place.
What he had already found out was that the damages on the mana vein were not only caused by one phenomenon, but multiple overlapping causes.
From the looks of it, someone, most likely the Oceanfolk, had aimed to weaken the combat prowess of the Mewi by damaging the mana vein by simply clogging it up.
That was, hands down, the easiest way to drastically reduce the amount of mana that could be naturally released by the vein.