Merlin
Kayden's barrier spell was broken, and only the dilation spell was left. Furthermore, he only had one more modification spell, the most special one and the one he had worked on the most all these years, his greatest possible destruction spell. His usual aura slash was compressed to the size of a finger, and its thickness became smaller than that of paper.
The density of the mana was so toxic that it would kill an apprentice before he was cut. As soon as it passed through the spell, the cut received a protective film that prevented its mana from spilling out. This allowed Kayden's attack to travel dozens of kilometers if necessary, and although it would have a loss in strength, it would be a small thing; only in the hundreds of kilometers would it be something more significant.