"Hahahah! Didn't you puny humans claimed that power was everything and such trickery was a sign of weakness?!" Kiva could already feel his body parts slowing down a little, and that was enough for Wolte's gun systems to place a shot at him, making Kiva fall to the ground.
Gan Yang's suicide attack was to ensure he petrified Kiva so that he could stop dodging their attack. Since the Ravenous Lord had yet to acclimate himself to his new body, it was relatively easy for Gan Yang to get onto him without Kiva noticing.
The rest of Gan Yang's crew decidedly tried to finish up their Captain's job after Wolte had pierced Kiva's wings. They were sure they could 'avenge' their captain as Gan Yang's petrification poison was working its way through Kiva's entire body.