In an instant, every survivor shot to their feet, including those who were genuinely injured. Some were even out of it, their heads still in a daze from the oppression of Ryuga, but so long as they had heard those resounding words from Finn, they immediately stood up without hesitation.
Only about thirty percent of the Ossuarists were left standing, the rest had died either during the initial battle itself, the abomination's rampage, its battle with Syf, or the last attack from Ryuga. For those who had perished in the final moments, their ends were a chaotic mixture of those forces.
Finn observed the carnage without batting an eye. There was no remorse or guilt to be found anywhere in his expression at all. This was a battle, and casualties were par for the course. In fact, even if there had been no survivors, he wouldn't have been bothered either because these were the same people who had decided to use his friends as hostages.
