Chapter 184 - First time with the new knives
Clearly, he expected something like this sudden attack as he said, "Dark Mantle!" using it to only cover his right hand which was already made of mana. He didn't want to get burned and the darkness from this technique and how his hand looked normally was imperceptible. His hand whipped out and slapped her on the side of her face just as she was about to spit that ball of fire at his head, so his slap forced her to shoot it off to the side.
Leona and Grant quickly retreated and just waited at the ready in case anyone else decides to intervene.
Boom!
That fist sized ball of fire exploded and burned several unlucky people who did not even know how that died as they were weaker rankers and instantly incinerated leaving nothing but bone dust behind.