Krune had also been practicing his Elements Regulation Technique, but it turned out harder than he expected. Let alone fusing all elements, he couldn't even make a fusion with two opposite ones with a proxy yet. Of course, he knew that it would take a long time to start with, so he wasn't disappointed.
Finally, there was his Purple Tribulation Lightning Laws. Krune was at least able to reach the Intermediate Stage with the Flash Annihilation and was close to comprehending a second one, Charged Lightning Energy.
Although it looked slow, Light Spirit was, in fact, impressed that Krune reached this level so fast.
Still, Krune knows that things would only get harder. After all, his Elemental Flowers are pretty much gone, just like Feifei.