The Shadow has returned

Vaar'nax, the Shadow Dragon, has come back to the Material Plane, stronger than ever. Behold, as the Shadow Ridge is once again within his grasp.

Centuries ago, an unintended feedback loop effect in Power Crystals caused his power levels to grow beyond his control. The energy he failed to contain broke free, causing major, catastrophic anomalies. For the sake of the Material Plane, Vaar'nax decided to venture into the Gallows, an another plane of existence, which was not material, and thus, his power leaks could not harm anyone there. Gallows were first created by Mordred, the deity of death, as the means to gather souls for his undead army.
The plane was some kind of mid-way, between the Material Plane and the Afterlife, which was the souls' default destination. Gallows were hostile to anyone within, though Mordred made it so it could be battled on the way to the Afterlife, however only the strong-willed souls were able to pass. The weaker ones remained and, after failing, returned to the Frozen Peaks layer of the Material Plane, being able to reattempt their journey after a century has passed.
The Gallows were just as hostile to Vaar'nax. Because he was an actual god, however, he could almost effortlessly bend it to his will. The Shadow Dragon exploited the Gallows' hostile nature to test his new projects under most unfavorable conditions, against a consciousness that thought similarly to Mordred, yet without the risk of actually confronting the god of death. The experiments were not the only thing he was doing there, however. Vaar'nax explored his own self, meditated upon every single trait he had, every deed he had done or not done. Slowly, he came to a greater understanding of his nature, his own divine power. He grew accustomed to his exponential growth of energy, learned how to contain such a great power. Meanwhile, the hostile nature of the Gallows forced subconscious adaptations on him. And after his last, most urgent project was finished, the Shadow Dragon returned to the material plane. But he was changed forever. He lost his old, perfectly black self to a brighter shade of grey and purple, while having grown an armored layer of thick, silvery scales rumored to be composed of extremely pure mithril. The biggest changes, however, happened within his mentality and even he himself does not yet know their full extent.