Ange didn't want him to die, Ange's exact words were 'Good opportunity, capture him'.
When his attack could be compressed by the Devouring Abyss into glowing beads, Ange was even more reluctant for him to die. These beads were excellent light sources; hang one in a cave, and even a pitch-black cavern could be transformed into a thriving world.
Anthony also didn't want him to die, as this Star Progeny Master was almost a key character running through the entire plot, from the formation of the Boundless Space Hole, the imprisonment of the Ancient Godlight, the experiences on the Gray Divine Star, to the hatching of new God Stars, he was involved throughout.
He was also the overseer of the Boundless Space Hole, experiencing its entire evolution. One might say that all the lives Ange nurtured in the Boundless Space Hole could find some answers from him.
Originally, Anthony hoped to capture him for in-depth interrogation, and now it's just fine, he went and set Ange's field on fire.
