Guren Ichinose: Catastrophe at 16 Vol 7

Ignoring her, Kureto remained at the front. He would lose if he did not go out. He knew it. To an extent, the enemy was strong. Therefore,
『Roar, 《Raimeki》!』
Kureto shouted. Then, from the sword that he was holding, lightning flashed. It struck his whole body and accelerated his muscle movement. His muscles were torn up, but the demon curse accelerated the forced healing of it. What he needed now was speed. To be faster than the enemy. To use speed to kill the enemy.
-Pg 75

So, he ran. Wielding a sword, he slashed the necks of 20 people, trying to reach the place where Hiiragi Mahiru was. But he cannot stop. The sword was charged with lightning and he swung it at Mahiru’s neck. Mahiru looked over. She laughed. Her head would be cut off!
“...............”
There was no response. She let it pass by, twisting her neck. She reached her hand out. She did not have a 《Kiju》weapon in hand. She did not seem to be using the demon’s power. Nevertheless,
“Die!”
Kureto swung his sword down. But, dodging it easily, she said.
“Older brother, you’ve came out so far alone–”
Without saying anything else, he swung his sword a second time. But it did not hit.
“What on earth are you trying to prove?”
The lightning bolt flew, but it did not hit.
-Pg 79

While dodging their attacks, Guren looked for him. The leader of all these soldiers. But he didn’t even need to search for him. Behind the crouching soldiers, stood a man who had the power to divide this place.
That man, had a sword that was charged with lightning.《Black Demon》
Amongst the demons humans can currently handle, it is the highest rank.
It was the same class as Guren’s 《Noya》, the man was carrying a demon called 《Raimeki》.
“......Kureto."
-Pg 196, 197

He pulled out his sword. Lightning flows out of it, and with that, Kureto’s body accelerated. Fast. It was abnormally fast. The other soldiers around him, looked as if they had been stopped; Kureto moved that fast. “Damn. Noya!” At once, the curse flowed through Guren’s entire body.
-Pg 198