When Sunny thought about it, a Stone Saint was one of the best possible forms he could attempt to assume to master the fifth step of Shadow Dance — even if he did not consider the nature of the battle against the Puppeteer.
After all, Saint was his first Shadow. She had spent close to a decade by his side, saving his life countless times — just as he had saved hers. Saint was not only his most loyal follower, but also his battle companion and, at many points, had been his teacher.
There were few beings in the world he knew better than he knew Saint. Not only that, but Sunny had also taken her into the embrace of shadow countless times, and as his power augmented her, he had fathomed the Stone Saints in great detail — body and mind.
Additionally, Sunny already shared a degree of kinship with these stonelike creatures. After all, he commanded the Jade Shell and the Jade Mantle — a piece of Nether's inheritance had already become a part of him.
