Strahd had not expected to see sunlight pouring through his bedchamber as Ajuni and Ghalwin stood before him. The paladin met the vampire blade to claw while Tobias wheeled through the air behind him, snapping sling bullets through a haze of false images. Sunlight poured from Ajuni and Ghalwin alike, hemming Strahd in; now bloodied and desperate, the vampire fled by phasing through the castle wall, escaping onto the parapets as thunder rolled over Ravenloft.
Ajuni smashed through his grand bedroom window in pursuit, glass scattering into the storm as rain lashed the stone. She and Strahd locked each other in a magical stalemate amid the wind and lightning, while his animated armor rounded the tower and unleashed crackling bolts toward Ajuni. Tobias shielded his sister with desperate magic as Ghalwin joined them outside in a burst of mist, driving Strahd back step by step with the Sunsword’s burning arc. Elsewhere in the castle, Izek, Ezmerelda, and Kiril caught up to Vasilka, clashing savagely as the flesh golem tried to reach Tobias.
The fight on the parapets turned cruel as Ghalwin beat Strahd back around the parapet's corner. Ghalwin invoked the names of the Ladies Three and Sergei's brother, but failed to land a killing blow; he stepped forward, and Strahd struck him down. He wrenched the Sunsword from the paladin’s grasp and hurled it into the abyss below Ravenloft. At the same time, the wider battle worsened. Vasilka smashed both Izek and Kiril into the stone, and Strahd’s armor sensed the invisible Ezmerelda, hammering her with lightning until she nearly fell.
As Ghalwin collapsed, Tobias flew around the corner with desperate resolve, holding the thighbone of Saint Markovia like a crude mace. With no protection of sunlight or backing of prophecy, the gnome attempted a single blow in absolute desperation; somehow, in a moment of pure being, he connected. Radiant vengeance poured through the relic, as the fury of the long-dead Saint burned through the vampire’s form. Tobias smashed in Strahd's face with the thighbone, scattering his vampiric teeth to the courtyard below. The vampire was reduced to a form of mist that retreated down towards the catacombs, and the last worldly trace of Alizandra Markovia faded to dust in the artificer's hand.
With his remaining magic, Tobias restored Ghalwin to his feet. Together with Ajuni, they turned on what remained of Strahd’s defenders. The knights of the Silver Dragon shattered Strahd's armor as the sorceress brought Izek back from unconsciousness. Rising in pain and rage, Izek targeted Vasilka with his cursed arm and set her aflame. Burning and terrified, the flesh golem staggered through the chamber and was immolated upon Strahd’s bed.
All of them were exhausted, barely able to stand, but Strahd would soon wake again. They descended down the hidden elevator shaft with the last of their artificer's magic, where Ajuni figured out that magic portals protecting Strahd's tomb led to other crypts. She found a safe connection, and they emerged into a tomb of fresh dirt, standing before a shining black coffin of finely waxed wood. Inside was Strahd's lifeless body, still too weak to re-animate. Ezmerelda drew a wooden stake, and each of the Heralds gathered around, gripped the weapon, and drove it into the vampire.
With their combined might, the stake pierced flesh, but not bone. A dark energy protected Strahd's heart as choking black mist poured forth and the shadow of Vampyr rose to bargain. The Dark Power first offered the magic items and portable fortress missed in Strahd's treasury, who's passcode would die with him; then, when that was rejected, by offering them the ability to save the ones they loved by becoming Vampyr's champion.
Most of the Heralds only suspected lies from Vampyr, but through the choking blackness, Tobias realized truth in its twisted words; by becoming a Darklord, he could indeed raise the dead of those they had lost, and make Barovia a better place. He also knew that Vampyr, if removed from Barovia, still would remain in the mists beyond the valley, and would be desperate to hunt them down.
Despite this realization, Tobias gave a speech of acceptance: both for what they had lost, and what they had become. United in purpose, the Heralds plunged the stake through Strahd's chest, sundering Vampyr's grip and piercing Strahd's heart. Castle Ravenloft shook as screaming blackness surged from Strahd's tomb, up the towers, and into the skies; in a matter of moments, only bones, dust, and noble garb remained. Strahd von Zarovich, the dark lord of Barovia, was dead and gone.