Kresnik is a shaman who transformed into a white-coated animal or (in some depictions) a vampire to fight the Kudlak. In Croatian and Slovenian lore, a person born with a caul was destined to become either a Kudlak or a Kresnik. A person so destined to become a Kudlak would already begin a career of evil while still alive, his soul would leave his body at night in animal form and fly through the air to attack people or to magically do other harm to the community he lived in. When he died, he became an undead vampire who was then an even greater threat to the community. But if a person born with a caul became a Kresnik, he became a champion of the community. While he lived, his soul left his body in animal form at night to fight against both living and undead Kudlaks.
Where the kresnik was the representative of goodness and light, the kudlak symbolized evil and darkness.
Kresnik is also the name of the Slovenian storm god, believed to be cognate with the Russian Perun. The precise connection between this figure and the vampire hunter is unknown.
Kresnik acts as one of the five demons that controls the Pentalpha system. Players can align with him to fight against mobs representing the other demons within the system. Those fighting against him will face waves of demons belonging to the Fairy, Dragon King and Beast races.
By acquiring enough power for him, players can obtain the ability to fuse him in a special fusion of Cu Chulainn and Unicorn.
Shin Megami Tensei: Strange Journey
Alongside Kudlak he appears in Sector Delphinus as an NPC. He has a role in EX Missions given by him and his archenemy. He requests the Hawthorn Spear for the final fight against Kudlak. After receiving their weapons the two will go to the far north of the 1st Floor to battle. If his mission is done then he will inflict great harm to Kudlak, who will retreat. If Kudlak has the Pest Crop he will poison Kresnik, who retreats. If they both have the weapons it will end in a draw.
Shin Megami Tensei IV Apocalypse
"A good vampire who was blessed by the light. His name means "cross." His rival is another Slovenian vampire, Kudlak, and their battle is unparalleled. They both turn into various animal forms, but his transformations can be recognized by their white color. It is said that evil can never overcome light, and each battle ends with Kresnik victorious."
—Shin Megami Tensei IV Apocalypse compendium
Kresnik can be found in the main temple of Tsukiji Konganji. He can teach Nanashi the Hamaon, Grand Tack, Sukunda and Heaven's Bow skills through his Demon Whisper. Kresnik benefits from learning Gun and Light skills, with greater benefit to Gun skills due to his Dexterity and Pleroma.
Devil Summoner: Soul Hackers
"A holy vampire hunter who was blessed by the light. His name means "cross." His rival is a Slovenian vampire, Kudlak, and their battle is unparalleled. They both turn into various animal forms, and Kresnik's transformations can be recognized by their white color. It is said that evil can never overcome light, and each battle ends with Kresnik victorious."
—Devil Summoner: Soul Hackers 3DS compendium
DemiKids Light & Dark
"Vampire-hunter in search of Bloodbat. Supposedly, he can transform into animals."
Kresnik can perform the combo Crosswinds with Cherubim.
Kresnik is the demon that temporarily possesses Mari Mochizuki due to her desire to kill the vampire Kudlak. In order to banish the vampire, he needs to consume white amnion while in her body and deal the finishing blow. To ensure Mari's survival, the party must retrieve her missing bag containing the amnion and assist her in the fight at Bugeikon on Day 5. Successfully defeating Kudlak before he escapes will unlock both Kresnik and Kudlak for fusion.
Devil Survivor 2
"A holy vampire hunter who was blessed by the light. His name means "cross." His rival is a Slovenian vampire, Kudlak, and their battle is unparalleled. They both assume various animal forms such as pigs, cows, and horses, but his forms can be recognized by their white color. It is said that evil can never overcome light, and each battle ends with Kresnik victorious."
—Devil Survivor 2 compendium
Shin Megami Tensei: Liberation Dx2
"A holy vampire hunter blessed by the light. His name means "cross". Kresnik and his rival the Slovenian vampire, Kudlak both had the power to turn into various animals. When transformed Kresnik was distinctly white and Kudiak had a darker hue. It is said that evil can never overcome light, and each battle ends with Kresnik being victorious. Nevertheless the battles between them were epic."
I am the Genma Kresnik, I shall protect you with the power of light.
I am the slayer of vampires... Call me if you are plagued by evil.
As he appears in Shin Megami Tensei IMAGINE
Portrait from Shin Megami Tensei: Strange Journey
Kresnik as he appears in Card Summoner
Kresnik as he appears in Devil Survivor
Kresnik as he appears in Devil Survivor 2
Kresnik in Shin Megami Tensei: Liberation Dx2
His appearances and dialogue often revolve around his eternal enemy, Kudlak. To contrast his rival, he usually has a benevolent and noble personality acting as something of a white knight. He also has opposing resistances, being weak to ice yet often strong against fire attacks.