Vampires in the Suikoden world are different from vampires known elsewhere--for example, crosses don't work against them (Christianity doesn't exist in Suikoden), and vampires can walk in broad daylight once they become powerful enough. They do need to feast on the living to survive, just like how vampires are typically understood. However, under the influence of the Blue Moon rune, their lust for blood is satisfied by the "compassion" that the Blue Moon rune grants upon them.
Official record states that Sierra Mikain is the original vampire (referred to as the "Coven Mistress"), was forced to become a vampire nearly 800 years ago. Vampires were not a violent race under the guidance of Sierra. However, after Neclord stole the Blue Moon rune, some vampires turned into carnivores, feasting upon the flesh of mankind.
This gave rise to vampire hunters. The first documented case of a human slaying a vampire can be seen in the "Nameless Land Chronicles," where a local noble by the name of Wilder is listed to have slain a vampire.
Vampires are powerful beings though, with vast powers which are intrinsic to the nature of vampires. All vampires have incredible strength and can cast a trove of spells, summon undead, and turn into bats. They also require special methods to be destroyed, and mere brute force can never destroy a vampire. For that reason, vampire hunting is a seldom chosen path by the average folk, and only those with great hatred towards the vampiric ilk would have the courage... or insanity to pursue their course. Here I will list the names of persons who are vampires, and those who hunt them.
No one knows where she came from originally. However, she was born as a human being, but came in contact with the Moon Rune at the age of 16. For centuries since she was unable to control the Moon Rune's lust for blood, and thus she took refuge within the forest to keep herself from taking blood from other living beings.
After Neclord stole her Moon Rune, she has been pursuing him for over 400 years, and was finally able to defeat him with the help of Kahn Marley and Viktor. After the Dunan Unification War, she lives among humans, observing them warmly.
After becoming a vampire, Rean took off on a journey to avenge the death of his master. After a few years, he returned to Sierra and together with her, explored the powers of the vampire. During these times, Rean and Sierra become lovers, and the centuries they spent together was Sierra's happiest times. After a few centuries, he became a valuable ally of Sierra in the Village of the Blue Moon. However, when Neclord stole the Moon Rune, he was among the few who refused to die, and took off to live as a predator of blood.
Sierra meets him centuries after this when she visits his manor close to the Highland/Jowston border. Rean was trying to hide from Sierra all these years to avoid destruction, and he tries to resist Sierra's attempt to destroy him. However, Sierra ultimately defeats him with the help of Nash Latkje, and he is destroyed by Sierra's "Song of Absolvement."
Since then, Neclord has become allies with Windy and Yuber, and together they have participated in much destruction. He also likes to abduct young women as his bride. He was the one who killed Kahn Marley's grandfather and father.
Recently, he destroyed Northwindow because he became bored. This resulted in him creating an unlikely nemesis, Viktor, who had enough willpower to become the bearer of the Zodiac (Star Dragon) Sword. This led to Neclord being defeated in doppleganger form during the Gate Rune Wars, and eventually led to his destruction when Viktor, Kahn Marley, and Sierra Mikain joined forces to seal his soul and destroy him.
On the surface, Ayana is a normal country girl, but when the time comes to prey upon visitors, she uses her vampiric nails to rend her victims or use a katana with superb mastery. She meets her match, however, when Nash becomes her next chosen victim. Nash destroys her by impaling her with a holy kobold figurine.
Viktor met Forryn, a swordsman, during his investigation. He was accompanying Roy, the son of Aegia. The three (along with the Zodiac Sword) team together to search for Aegia, and Roy found her. However, being a boy, Roy succumbed to Aegia's vampiric beckoning. However, Forryn and Viktor managed to dispatch her before Roy was turned into Aegia's vampiric son.
He came to Jowston shortly before the Dunan Unification Wars after following Sierra Mikain all the way from Harmonia. He wanted to ask Sierra where Neclord may be, but he lost track of her somewhere around Muse, and ended up in Greenhill, where he lent a hand to the Greenhill army to defeat Rowd's initial attack on Greenhill. After that, he crossed over to South Window to seek the Zodiac Sword, and met Viktor, helping him fight Neclord at the old Northwindow fortress. After Neclord escaped, he had been searching for clues on Neclord's next move, but after hearing that Sierra was in Tinto, he headed there and tried to ask for Sierra's help but to no avail. He sought the help of Viktor and the Zodiac Sword, and was finally able to convince Sierra to help him fight Neclord.
In the final confrontation, Kahn used his family secret technique to seal Neclord's soul, preventing him from using his "doppleganger secret." Sierra took the Moon Rune from Neclord, and Viktor finally put an end to Neclord with the Zodiac Sword.
After the war, unbound by his past, Kahn is studying to become a mineralogist.