Anger leads to hate...
In a dark chamber on Vjun, a gloved hand crumpled a small sheet of flimsy into a tiny ball, the fist tightening until electronic feedback made his remaining flesh ache. Unable to remain still, the armored shadow emerged to roam endlessly through the halls of his castle, glowering even through the mask. Outside, the few inhabitants sensitive enough to feel the whisperings of the Force cowered in fear beneath the wrath of the Dark Lord in their midst. Had he been on the Executor, there would have been whispers that someone would die that day, and every officer would have prayed that no mistake, however minor, would occur on their watch, for anything could spell their end when such a mood was upon their leader.
Back and forth he paced through the shadowed passages, his rage warring with his sorrow. He had been lied to by the one to whom he had lost everything, betrayed by his once-friend, whom he had once called a brother. He had not killed her: if he had, this message would not be possible. He had been lied to, had been deceived, been betrayed, lost, cursed, condemned...the tumult in his heart and mind grew stronger until he could no longer move, falling painfully to his knees, hands clasping the sides of his helmet as if to block out an unbearable noise.
Images flew past his closed eyes, blurring until he could hardly make them out. She stood and smiled at him, glowing with the news, driving away the shadows for just a moment. Her face contorting in fear as his invisible grip stole her breath away. Kenobi's implicit disgust, turning on his heel to leave his brother to die. Palpatine's cruel smile, lying to him about her fate.
As quickly as it came, the storm began to subside, leaving him empty save for an icy rage that could have frozen Tatooine with its sheer power. Darkly, he realized that he had killed Kenobi far too quickly, allowed him a merciful death when he should have suffered for all eternity for hiding the only thing that could have convinced him that he had not committed, to his mind, the ultimate sin. He wished desperately that he could reach out and strike down his second Master as he had his first, destroy him in a thousand terrible, violent ways, though he knew too well such an attempt would mean his own death, and that was something he doubly did not want to risk, not now. The darkness rose within him, surging stronger than it had in years. He welcomed the power, the rage, the all-consuming anger, the only defenses he still possessed.
For if he focused on that anger for long enough, perhaps he could accept the fact that his only child was a stranger. Perhaps the heady surge of power could overshadow the searing pain that lanced through him every time he thought about what it was that he had lost, magnified now in light of this new revelation.
Perhaps, even, he could forget that it was this same anger that took it all from him.