If the player is bitten by a vampire, contracts Porphyric Hemophilia, and does not cure themself of the disease (using the same methods by which they could cure any other disease) within three days, they will become a vampire. While this is normally a permanent condition, it is possible to cure the disease even after becoming a full vampire.
Once Hassildor comes, he explains them that he and his wife are vampires. He lives with it, but his wife, Rona Hassildor, could not, and slipped into a coma. Hassildor wants the cure, and tells the Hero of a witch that lives near the Corbolo river, south of Cheydinhal in Drakelowe.
The witch, Melisande, requires five empty Grand Soul Gems before she will help with the cure. Once these are delivered, she asks for a number of ingredients to make the cure. Most can be purchased, but it's important to note that it is not easy to buy items when the Hero is in advanced stages of Vampirism.
The Hero must kill the vampire Hindaril, found in Redwater Slough off of the Panther River. Hindaril is behind a door with a very hard lock. The key is beyond an underwater passage and in a chest. Once he is found, it is best to attack immediately before he arms himself.
Return to Melisande and talk to her. After a day, she will have a potion ready. She will give the player both a consumable version, and a Misc. Item version for Rona; however, drinking the potion early may bug the quest. Return to Skingrad and talk to the steward again. She will lead the Hero to the Chamber of the Lost, where Melisande will attempt to cure Rona.
After two days, the count will tell the Hero to return in another 24 hours and talk to the steward. Doing so will reward the player with a decent amount of gold - 1000 or higher, as the amount is leveled.
The cure potion may now be consumed safely. Note that after being cured of Vampirism, it will be impossible to contract Porphyric Hemophilia again normally. However, asking to be turned into a vampire by Vicente Valtieri will still work.
With the official Vile Lair add-on, after upgrading it, it is possible to cure vampirism at any time using the Font of Renewal in the Vile Cloister and the Purgeblood Salts found near it. This can be done as many times as desired. Note that this does not finish the Vampire Cure questline, or remove it from the quest log; it simply cures the Hero's vampirism.
Occasionally, the Count will not acknowledge that the player has the cure. This is caused by having the Information at a Price quest currently active. If this bug manifests, it will be impossible to complete either quest. This can be fixed by reloading a save prior to having the cure potion created. Complete Information at a Price, and it will be safe to finish the cure. If Hassildor has his six or so normal conversation topics, instead of immediately taking the potion, then this bug has occurred.
If one of the player's Grand Soul Gems is stolen and the rest bought or found, they will keep the four unstolen ones and only give up one of them to Melisande. (Works on PS3, PC and Xbox 360)
The count will keep rewarding the player with unlimited gold every time he is asked about the "Reward," if the dialog is kept open.
On the American Game of the Year Edition for PS3, and on the XBOX 360 Classic Edition, Melisande won't recognize the bloodgrass in the player's inventory, making the quest impossible to complete.
Workaround: Sometimes the game will simply not recognize the bloodgrass in the player's inventory, but will fix itself if the player acquires new bloodgrass.
Alternate Workaround: using a non-GOTY version of the game to complete this quest may allow it to be completed, though this risks deleting all Shivering Isles-related items and resetting quest progress related to the add-on. Completing Vampire Cure before starting the add-on is recommended.
PS3 European Workaround: For PlayStation 3 users in Europe, including UK, there is a complex way of getting around the bloodgrass bug. First, save the game (saving into a new slot is recommended) just outside of Melisande's hut. Then, quit the game and go to the PS3 system settings, and change the language to German. Reload the game, and proceed into Meilsande's hut and talk to her; "Blutgras" (German for bloodgrass) is now a highlighted topic, so speak to her and exhaust the topic so that it turns grey again, by which time she will have taken the 2 bloodgrass samples. Then save again, quit the game and revert the system settings back to English, reload the game, and proceed with the quest.
Known issues and ways to work around them: In some cases with this workaround, if the player has begun any quests in the Shivering Isles, the expansion resets and must be played from the beginning again; all items/quests from the Shivering Isles will be removed from the journal, and there are also cases with some SI quests having minor bugs later on. The only way to prevent this is by not entering Shviering Isles until after finishing the Vampire Cure quest.
PC Workaround: For PC players, to avoid all bugs in this quest and immediately cure the character of vampirism, simply type player.additem 000977E4 1 in the console.
Upon returning to Melisande's home after twenty-four hours, the player may find that she is still in her basement, which is inaccessible.
This bug has been patched: According to patch v1.2 (3/23/07), this bug has been fixed.
Sometimes, if the Count appears and gives the reward prematurely, the quest will be "completed," but the player's vampirism will not be cured. If this happens, the potion can be remade by bringing Melisande another set of ingredients. Be aware that Hindaril needs three days to respawn before his ashes can be re-obtained.
Sometimes, after being cured, the character my have some slight to major facial differences, and look more like the "stock" character before customization. The hair will generally stay the same style and color, but the face itself will change. For some reason, this problem sometimes may fix itself after sleeping for several hours at least. Saving the game, loading a save prior to being infected with vampirism, and reloading the current save has been known to fix the problem on all systems.
Sometimes, after curing Rona Hassildor and waiting 24 hours for the reward, Janus Hassildor will not give it. Hal-Liurz will not go to the private hall to fetch the count, instead she will go to the Chamber of the Lost and will not leave, but still tell the player to wait there while she gets the count. Even if the player enters the count's hall and talks to him, he will not speak to them. This may cause all other count-related quests to become impossible. This appears to be caused by looting the countess's body after she accepts the cure.
Workaround: If the count has become unresponsive, he can be reverted by attacking and yielding to him. However, attacking him will provoke significant reaction from the guards around him. This can be avoided by using a 100% Chameleon effect. While hidden by the effect, punch the count. He will attempt to flee to a guard, but Chameleon will prevent the player from gaining a bounty, so the guard won't react. If the player drops a weapon on the ground, then punches the count again, he will pick it up. Then, yield to him and quickly speak to him. This should trigger his reward diologue, and allow progress with other quests that require speaking to him.
Drinking the potion before finishing the quest may prevent its completion. If this happens, all vampirism cure potions in the inventory must be destroyed using the 'player.removeitem' command. When talking to the steward, the option to say "yes I have the potion" should now be available. Spawn a new Vampirism Cure Potion and talk to her again to continue the quest.