After devouring Rodrick and Dimitri, Cain felt their souls being painfully consumed by Scarlet Reaper inside his stomach. The sensation filled him with a monstrous killing intent, which he directed squarely at Marya. The pain from the spear strike still throbbed in his right shoulder, with white embers searing through the wound as a painful reminder of the near-fatal attack.
Cain knew he couldn't stop the spear as the power it carried was simply too much, so he had found another way. Sacrificing Sky Breaker allowed him to divert the spear's trajectory just enough to save his heart and instead take the hit in his shoulder.
Using his Legendary Innate Ability, Illusion Master, Cain created a ruse, tricking the trio into believing he was dead. As they approached to inspect his body, Cain had stealthily moved behind them, activating his full dragon form. The suddenness of his attack was his crucial advantage, allowing him to devour Rodrick and Dimitri in one swift motion.