Everything at once
Jason knew that he had no time to waste because the Doom Crawl he was faced was much stronger than he thought it would be.
He utilized his mana eyes' abyss ability and Petri's petrification curse in order to intimidate the Doom Crawl for a short moment.
At the same time, he exerted the race specific weakening curse to its fullest extent by using a majority of his stored mana.
This weekend the Doom Crawl's physical strength by a large margin.
Only a moment later, Jason's stigma and the transmuted Celestia aura were fully unleashed as he used up every little trace of mana within his mana core to enveloped Byakur with Solaris' compressed black flames.
By utilizing every trump he had, at once, Jason was able to take on the Doom Crawl by surprise.
It had already been astonished that Jason's long-range attack could injure it, but at the same time, the Doom Crawl had thought that it took a large margin of Jason's mana!