Shaitan snuck away at one point to visit her old village project only to find that the three villages were struck with a terrible cancerous plague that kept them alive (as the cells kept replicating) but in perpetual anger and pain as their bodies twisted and bloated, their children wracked with a pulsing corruption beneath the skin similar to what happened to his own skin when the weapons were implanted. This was the Duchess of Knives' revenge against her.
The two Fell Knight lovers who had served Shaitan were nowhere to be seen. Shaitan learned that Shaeotiel hadn't been seen since a few weeks after Shaitan's first experimental procedure while Arekhala had fled to the Iron Legion where she campaigned to have Shaeotiel found.
From that point on, more than at any other point, Shaitan was consumed with a need for revenge. While before Shaitan used any opportunity to lash out at the Silver Legion, now Shaitan actively sought out those opportunities, sowing discontent by the cunning application of truth or simply through insinuation that a fallen's worse fears were true. Since the Silver Legion were often quite brutal and paranoid, it didn't take much imagination for them to feel betrayed. Shaitan naturally took quite a bit of glee in losing glamorously during the Long March in a way that assisted their success in securing a number of human settlements. Shaitan was knocked down to Fell Knight for that (and suitably tortured) but he took later opportunities in the war to show her value to the Ebon Legion and thus was re-instated at her previous rank.
Shaitan had set himself up to be the symbol for what others should avoid becoming. She took risks that no one else would have taken because, in the end, he hoped to be destroyed. Her words were more often true than false and within that lay the seeds of a legend ... at least in a few people's minds. (The next bits are of the Storyteller's invention).
Viriel, an Iron Legion defiler, was one such person. Seemingly struck by the cruelties in the world and desperate to prove that redemption was possible, Viriel focused all of her efforts on Shaitan. She would occasionally creep close to his camp, spending time in quiet observation or conversation, and while Shaitan at first chased her off - thinking her a spy - later they actually spoke. Viriel believed in Shaitan, truly believed, and wished with all her heart to save him.
When Shaitan froze a small battlefield by screaming out his horror that this is what they had all fallen to, sibling against sibling, the silence was broken by Grifiel (enraged at the brief shaking of his worldview) charging toward Shaitan and ripping off her wings before flinging her to the ground. Viriel raced between them and begged for Shaitan's life, finally dragging a barely conscious Shaitan away to an Iron Legion fortress where she convinced the others to let her tend him. Yet when Shaitan finally returned to full strength (though still wingless), Shaitan slashed her back with his sharpened tail, outraged that she had denied him the opportunity to die. Ashamed of what he had done, Shaitan fled, leaving her shocked and confused.
Yet all things couldn't last forever. The war ended with the angels capturing all of the remaining fallen and holding them by a portal which opened out into the Abyss itself. When Shaitan passed through that portal, he felt something unexpected.
The war was over. She could be at peace. There was nothing more to do, nothing more to fail, nothing more to fear. Shaitan sat in the blank expanse of sensory deprivation, hearing only the wails of his brethren, and simply retreated inwardly. In all of the eons within the pit, Shaitan never spoke, simply dreaming her way through the screams of hell. For a time, his old vassals would scrabble and beg and whine and wail at her, but after awhile even they began to drift away ... mostly.
Part 1 can be found here.
Part 2 can be found here.