Leif Helgarson is one of the main characters in The Iron Druid Chronicles
Leif Helgarson is introduced as the vampiric attorney at Magnusson & Hauk, usually working at night, due to his condition.
He speaks in an old-fashioned way, sometimes even composing his sentences in blank verse and doesn't know a thing about modern vernacular.
He is also one of the oldest and most powerful vampires in the world, and most certainly the oldest west of the Atlantic Ocean. Mr. Helgarson holds the territory of Arizona.
He was originally a Viking colonist in Iceland in the 10th century. He had a wife and two sons, and was a proud man, boasting that he had seen the New World with Leif Eriksson and had killed twenty-seven men on raids. This caused his ego to swell. One night while drinking with two friends and two strangers, telling tales of vampires and werewolves Leif spoke of how great it would be to be a vampire. One of the strangers asked him why he would sacrifice his humanity and his place in Vahalla (the Norse version of Heaven) in return for living for centuries and great strength. Leif responded by saying that due to his responsibilities with his family, he could not, but "if I was just starting out again, nothing holding me back, then why not?" The stranger then revealed himself to be Thor, telling Leif he was now free from his responsibilities and that his family was dead. Leif did not believe him and but excused himself from the bar to go home, only to discover his family dead. Leif swore vengeance against Thor and set about trying to become a vampire to further this goal.
He traveled to Prague, where supposedly a powerful vampire lived. There he worked as a guard at a dock learning the language. When he learned it well enough he started asking questions to the locals about resting place of a vampire. Where his questions were met with silence he returned knowing that the patrons believed in the existence of vampires. He noticed a trend, that those who believed were in bars near modern day Prague or Hradcsny castle. After two months of inquiring he met a well dressed small man representing a "Scholar". He introduced Leif to him and the Scholar turns out to be a vampire. He promised to turn Leif into one if he could learn how to read and write in three different languages and give three centuries of service. Four years later in 1010 he learned the scholar's name, Zdenik, and Leif is turned. After three centuries during which he fought other vampires, lone werewolves, ghouls, and witches, Leif was released from his service and began his search for Thor. He discovered that Asgard is sealed off from the rest of the world and can only be reached by crossing Bilfrost or being sent by the Valkyries. He then turned his search to magic users that can move between the planes other than the conventional routes. He learned that the only individuals who can shift to all planes are the Tuatha Dé Danann and druids. In the 18th century he claimed he had met the goddess Flidais, and while she refused to take him to Asgard, she revealed that one there was one druid left in the world. She did not know his location, but guessed he was likely in the New World in a tropical zone or desert to avoid the Fae. In the short story A Prelude to War, this is revealed as a lie. He had actually consulted Mekera, a powerful seer in Africa, in the 1990s and used his vampire glamour to make her divine where the last Druid in the wourd would show up, and she told him Tempe, Arizona.
This led Leif to move to Arizona and wait, hoping the last druid would appear, and this turned out to be Atticus.
Leif appears as a typical Norseman. In Hammered, he tells how Zdenik (his creator) described him. "Tall, blonde and Viking."
Leif is first mentioned by Atticus as his friend, lawyer, and sword sparring partner. He is described as an "actual Viking" who is still alive due to his vampiric immortality and one of the only skilled swordsman Atticus knows who is fast enough to give him a challenge. He also mentions that he often pays Leif with his own blood; being from 2100 year old druid, it not only is appealing to Leif's taste but makes him stronger. Leif later meets with Atticus at his house shortly before an attack by Fir Bolgs, and Atticus's offers to pay blood for assistance in the fight. Leif agrees and displays his superhuman strength and speed in killing some of the Fir Bolgs, then helps conceal the results from the police by hypnotizing Atticus's nosey neighbor, and calls in his ghoul friends to dispose of the bodies. He later provides similar services after Atticus is shot by erasing the paramedic's memories and calling in the ghouls again to remove the carnage from the final battle at the end of the novel.
Leif is present at the start of the novel trying to convince him to join him in attacking the Norse thunder god Thor. When Atticus declines, Leif feels insulted and disappears for most of the novel, refusing to talk to him. He only contacts Atticus through a phone call, asking him if he's changed his mind regarding Thor. When Atticus needs help attacking the German Coven's stronghold, he finally caves and agrees to help Leif kill Thor if he assists with taking out the coven. Wearing a steel breastplate to prevent staking, an iron amulet and wielding a borrowed Moralltach, Leif assists with the assault using his massive strengh and speed to fight the witches, their demonic spawn and two enormous golems. However during the event his clothing is ignited by hellfire and he is forced to flee the scene as he is very vulnerable too it. He is found badly burned and unconscious, but Atticus is confident he will recover.
Leif makes a major appearance in Hammered, having convinced Atticus to help enter Asgard and kill Thor. During the storytelling session around the campfire, where all the assembled men wishing to kill Thor must tell their reasons, Leif is the last to speak and his reason the most serious. It is here that he reveals almost all his background and how he became a vampire (see "Background" above), with Atticus hearing it for the first time. This tale also reveals his first meeting with Atticus was carefully planned for no other reason than he needed a druid to get at Thor. Atticus is angry with him at first, but Leif insists that in the course of their 10 year relationship that he truly does consider him a trusted friend and not merely a tool in his vengeance. To prove his trust, Leif promises he will reveal any secret about vampires that Atticus chooses to ask about. Atticus asks him the location of Theophilus, allegedly the oldest vampire in existence. Leif reluctantly reveals the limited knowledge he has about his location, though admits he has never met him. During the attack in Asgard, Leif takes on Thor directly using the sword Moralltach. After a prolonged fight, Leif makes a final suicidal charge, trading his own safety for the chance to wound Thor. The plan works, as Thor takes a wound in the shoulder that later kills him due to the sword's magic, but Leif's head his crushed beyond recognition by Thor's hammer in the process. Atticus recovers his body and notices his chest still has the same magical aura he had before and theorizes he may actually be able to heal and regrow his own head, but this is only a guess. He takes the body back to Arizona at the novel's closing.
After being told by Hal that Leif did indeed survive and regrow his head, Atticus arranges to meet him at a bar in Flagstaff. Upon arriving at the bar, Atticus discovers that Leif is not fully healed: his face still badly disfigured and his powers are weakened. He also learns that Zdenik, Leif's creator, has moved to Arizona with the alleged reason of protecting Leif's territory, but his actions suggest he intends to simply take the territory for his own. Leif asks Atticus to help him kill Zdenik, but Atticus vehemently refuses, having already gotten into enough trouble by helping Leif kill Thor. They are interrupted by one of Zdenik's lieutenants, who overhears that Atticus can kill vampires with his magic (they are technically "dead" already so the Druidic rule against direct harm by magic doesn't apply). Atticus cannot allow this knowledge to get out, and so subdues her, but insists that Leif be the one to kill her because he doesn't want to get involved. Shortly thereafter, Atticus is attacked in his hotel room by a powerful vampire who tries to drain his blood. After a distraction by Oberon (who is severely injured in the process), Atticus barely managed to finish his spell in time, which lethally unbinds the vampire's body at the cellular level. Leif reveals himself at that moment, statting the vampire he just killed was indeed Zdenik and that Leif orchestrated the encounter, knowing Atticus would kill him. Atticus then blacks out from blood loss. Later in the hospital, Granuiale tells him that Leif somehow healed his neck wound and arranged for the scene to be cleaned up before the police got involved. Atticus swears to kill Leif if he ever sees him again and calls Hal to say he is terminating the attorney-client relationship with him. In the epilogue, Hal passes on that Leif quit the law firm soon after, but also conveys his apologies to Atticus and promises to stay out of his way.
Leif appears at the half-way point of the novel rather suddenly, fully healed and having inexplicably found Atticus in Greece. He approaches Atticus literally holding a white flag in his hand and a burner cell in the other. Leif pleads wth Atticus not to kill him and explains he is acting under the orders of Theophilus, and that the burner cell is for Atticus so that Theophilus may speak to him. Atticus learns that Theophilus was the mastermind behind the Roman war against the druids, and refuses his "deal" to not train any more druids. He is then ambushed by Dark Elves. After Atticus and Granuaile escape, Leif blows up the store where the ambush occurred to conceal the evidence of the dark elves and then kills three more of elves that are chasing them. He warns Atticus about another ambush in the wooded area he's headed to, as well as revealing that Theophilus is not acting on his own, but rather under someone in Tír na nÓg. Atticus swears he can never forgive him for what he did back in Flagstaff, but Leif says he does not need to be forgiven. He kills a few more vampires in the wooded area and then leaves Atticus and Granuaile alone to handle themselves from there.
Atticus first becomes aware that Leif is still tracking him after finding a cryptic note pinned to a tree in Germany along his route through Europe. Atticus recognizes it as Leif's handwork by the use of Old Norse and a Shakespeare quote, and interprets in at a warning of danger ahead. The warning turns out to true as 5 snipers were placed in the area. Later in a cafe in France, Leif suddenly walks in and reveals he determined Atticus's location by tapping Hal's phone. He claims that while he is working with Theophilus, he is not loyal to him and is working to try to save Atticus without revealing he is doing so. He also warns Atticus about a man named Werner Drasche who is also working with Theophilus, and explains Drasche's powers. Eventually, Granuaile gets him to leave by bringing up vampire physiology (particularly, what remains of their reproductive organs) and going into gruesome detail about her speculations, something Leif has always been extremely squeamish about.
Leif never actually appears in the novel, though his betrayal is mentioned several times. Atticus also informs Hal about Leif's eavesdropping on their previous call and suggests he rebuild his firm's entire security plan from the ground up, even suggesting Leif might have placed a backdoor in the firm's computer systems before leaving.
Atticus has Hal contact Leif to obtain contact information for Werner Drasche, since he has no other way to speak with him. Leif does so, and passes on seemingly sarcastic congratulations for Atticus having killed so many vampires with the information he passed on to the Hammers of God. Later, Atticus decides to call Leif directly and brazenly ask him for the location of Theophilus. Leif claims to have been "cast out" of Theophilus's group and is still residing in Normandy, a result of him being blamed for what Atticus had done up that that point. He offers a guess that Theophilus might be in a specific hotel in Prague. The hotel turns out to be an ambush, with Atticus barely escaping. Feeling he was betrayed, Atticus seeks Leif out with the powerful seer Mekera (since undead can't be divined, he targets Leif's next feeding victim), finding he was telling the truth about being in Normandy. Atticus confronts him about the betrayal with Zdenik, which Leif counters by pointing out Atticus's hypocrisy with his own manipulative behavior and how his vendetta against Theophilus is just as personal. The two then get into a prolonged fist fight, neither attempting to kill the other but venting their anger until both of them are exhausted. Atticus then accuses him of betraying him about Prague, but Leif claims he was telling the truth, and that Drasche had tapped his phone, and so had set the ambush. Leif had actually intercepted Drasche's own phone call later about the ambush, but had no way to contact Atticus to warn him, so had left a message with Hal (not knowing he was dead at that point). Leif surmises that Theophilus was traveling to Rome for a final confrontation, and Atticus gets an idea to make a deal. At the end of the book, after Theophilus has been killed, the deal is revealed: Leif, now the oldest and most senior vampire in the world, creates a peace agreement, with all vampires withdrawing from western North America and Poland, and no more vampires in excess of 1 per 100,000 humans in the rest of the world (a rule known as the "Accords of Rome"). The treaty is signed by Leif, Atticus, Granuaile and Owen, but not before Granuaile gets in one last awkward question about whether or not vampires defecate.