Heh, I thought that a few of you had figured out this twist, especially with all the references to diseases and wisdom boosts earlier.

It also explains a certain change in terms of a certain sword.
Aramis Simara said:
Does this make Dar a "Doomed Rat Bastard"?
Read this update, and you tell me.
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Chapter 83
THE FURY OF THE DUKE
Dar had shifted form into that of a rat-human hybrid, the culmination of the change wrought upon him by the wererat that had bitten him in Rappan Athuk.
The infernal warriors were not fazed by the change, and continued to press their attack. Now it was their foe that resisted their attacks, their sword of infernal iron of little use against the unnatural resistance granted by the lycanthropic curse.
Dar had lost none of his own fighting skills in the transformation, and had gained a blazing increase in speed and agility. His enemies had flanked him, but he did not give them time to exploit that advantage, overwhelming the foe in front of him with a violent surge of attacks before the one behind him could drive its weapon home. It cost him; he took two hits from the one at his back, which hurt him some even through his newly augmented hide. When he finally drove the first infernal warrior to its knees with a blow that crushed its breastbone, the other one leapt at his back with its sword raised to fnish him. There was no time for Dar to spin to face it, but in a blur of motion he reversed his stroke, driving his sword up through the body of his second adversary. The half-fiend clutched at the wound, then its sword fell from its hand to clatter on the ground, followed a moment later by its body as Dar yanked his weapon free.
Snarling, Dar leapt over a fallen chair, and rushed around the conference table toward the Duke. The Duke had taken down a weapon off the wall behind him, an ancient greatsword with a slightly curved blade. The infernal lord turned toward the onrushing half-man fighter and watched him come, his burning eyes shining in the deep caverns of his face.
Besides Dar, there were only four of the invading force left standing, and their situation had become truly grim. Talen and the last two soldiers from his line had been driven inexorably back, forced into a defensive triangle as the half-fiend warriors formed a ring around them. One could barely stand, his left leg covered in blood where his hamstring had been sliced open. The other soldier was barely past his teens, and while the skin of his face and neck was blackened with burns, he had otherwise been able to thus far escape additional injury.
But they still faced five of the hellish warriors, none of which had been seriously hurt. And as Talen lifted his sword into a defensive stance, he saw another foe move forward to join the battle.
“Ah, the loyal captain,” Sobol said. “Taking up the cause after the death of your beloved marshal. A shame that Velan Tiros did not live long enough to see the final end of his little cabal.”
“Face me, and we’ll see...” Talen began, but as he spoke he met the narzugon’s gaze, and everything else seemed to fade away, and the devil swelled, until it dominated his view. He could hear the creature’s laughter, and felt his own heartbeat pounding in his ears as blackness crept upon him.
The last scout had been driven back into a corner by the two warriors that had killed Suhn. She favored her side where one of them had gotten to her through her light armor. She’d tried to remain mobile, to keep her foes at bay with rapid strikes and retreats, but while one of the pair was at least as hurt as she was, the other had suffered only a minor scratch just above its left eye that barely bled.
“No place left to run,” it said to her, as the pair closed in, careful to leave her no avenue of escape.
Dar crouched and leapt at the Duke, who brought his sword around in a smooth blocking strike. The wererat shifted and immediately came in again. The two exchanged a violent fury of blows, and when they broke again it was the Duke who bore a fresh wound, a cut on his right arm that oozed bright red blood. But as the two combatants shifted position for another exchange, the flow of blood ceased, and the wound knit shut.
“You cannot defeat me,” the Duke said.
“If you can bleed, you can die,” Dar hissed at him, and leapt to attack once more.
This time, neither combatant held back. Dar took a hit that bit into his flesh, the Duke’s sword tearing a gash six inches long in his side. But the warrior in turn unleashed a devastating combination of power attacks, one of which connected hard, piercing the Duke’s chest, his sword driving deep into the man’s body. The Duke staggered back and almost fell, blood pouring down his body from the vicious wound.
Dar leapt onto the edge of the table, and lifted his sword to finish his adversary.
A huge crash sounded, and the chamber almost seemed to shake. Before Dar could strike, the Duke reared back up. He clutched a necklace at his neck, shattering one of three black iron globes dangling from the golden links with a crushing squeeze of his fist. At once the Duke began to grow in size, his arms lengthening and thickening, his torso broadening, his tanned skin replaced by a dense gray hide. His skull shifted as well, sprouting a pair of massive horns. A long tail and wings sprouted from his back. The new form of the Duke was over nine feet tall, and he loomed over the wererat fighter crouched upon the table.
Dar screamed and threw himself upon the creature, but before he could strike, the cornugon seized him in its claws.
“Wretched mortal,” it said, its voice causing the room to shake—or maybe it was just the creature’s grasp. Dar squirmed and tried to break free, but the monster’s claws held him like iron bands. “Now you see the folly of your pathetic efforts.”
Dar struggled, and the devil squeezed its hands together, digging its claws into his body. It leaned forward, until its jaws were inches from his face.
“Where is the marshal’s sword? I know that you have taken custody of the blade. Yield
Valor to me, mortal, and I shall let you keep your wretched life.”
“Go screw yourself,” Dar said. With a sudden motion he yanked his right arm free of the devil’s grasp, and brought his sword up to strike. The attack came down on the Duke’s head, but as it hit it glanced off one of the curved horns. The sword shattered, the blade snapping off halfway down its length.
“So mote it be,” the devil hissed. It slammed Dar down on the table with enough force to crack the ancient stone. Dazed, the wererat fighter could do nothing to alter fate as the cornugon lunged forward, its spiked tail darting over its shoulder, down into its prey, driving through his chest and through his heart, finally erupting out of his back, digging deep into the mass of the table.
The corugon snapped its tail up, launching Dar across the room. He landed hard on the ground, blood splattering over the marble tiles. His body shimmered, and he returned to his human form. A hole penetrated his chest where the devil had impaled him.
His lips moved for a moment, but no sound came out. And then he died.