Conquest (3)

It took Nial and the ten Infernal Devils less than a day to annihilate the Heligav across the entire stellar system. 

Some may ask if it was truly necessary to annihilate the entire Heligav race, but Nial could answer this with a decisive 'yes!'.

Nial was pretty certain that it was necessary. 

First of all, the survivors of the Heligav race would have formed a never-ending grudge against him if he were to keep some of them alive. Nial would have turned into their mortal enemy until one of the two sides were to cease to exist.

Nial skipped a few steps and annihilated the Heligav race from the get-go. Of course, there were still a few more territories that had to be cleansed thoroughly but Nial had already sent the Infernal Devils to cleanse them as well.