As expected, the giant Kobold was intimidated by Monn's shout of the Demon Sealing Dance.
In addition, Monn acted as if he didn't care about his own life. He used the flaming divine sword as a burning stick and moved his arms to cover his legs.
This made the giant Kobold feel that Monn's Demon Sealing Dance wasn't about to take him down with him. It would seal Monn and itself as well.
It was purely out of Monn's usual style of treating his enemies as if they were worthless.
This caused the giant Kobold to make a mistake in his judgment.
While he was thinking, his slow movements allowed him to dodge.
Monn's dimensional slash brushed past the giant Kobold's calf and landed solidly on the spatial barrier behind the Kobold.
The fire attribute shockwave from the flaming divine sword reached the Kobold because it thought that it had powerful reinforcements.