Lazarus

Lazarus is the leader and co-founder of the anti-monster terrorist organization Ilias Kreuz. Despite his calm and charismatic nature, many people who have interacted with Lazarus (Luka included) consider him to be insane. He was a close friend of Luka's father, Marcellus, who appears outraged at the disparity of power between monsters and humans due to tragic events in his past.

Past
He along with Marcellus, Merlin, and Karen slayed Alice XV (Fifteenth), but realized too late of her wishes of coexistence. As they were about to spread these wishes, the young Alice XVI (Sixteenth) came and attacked out of blind rage after seeing her mother dead by their hands, unintentionally killing Merlin and Karen, the latter a woman whom Lazarus and Marcellus loved. The attack also left Lazarus's left arm inoperable.

Angered, they did not spread Alice XV’s wishes and founded Ilias Kreuz out of vengeance. However, Marcellus sometime met Lucifina and eventually "betrayed" the ideals of their organization by helping monsters. Lazarus eventually discovered this and Marcellus told him that their revenge plan isn't what Karen and Merlin would have wanted. In frustration, Lazarus strikes out at the traitor, knowing that his friend would have easily dodged, but to his surprise Marcellus takes the blow. Before he died, Marcellus told Lazarus that the young Monster Lord's attack that left Lazurus's left arm inoperable also left himself blind in his left eye, but did not tell him because he didn't want him to worry. Marcellus's death then left Lazarus in despair and drove him insane.

Chapter 1
Luka first encounters Lazarus at Port Natalia, who bombs a mermaid school and quickly flees the scene. Heading to the inn, Luka informs Alice, who had become his traveling partner, of the terrorist organization and their leader.

After the events of the Pyramid, Luka meets Lazarus again at a Mermaid Bar within the kingdom of Sabasa. He gives Luka a cup of orange juice and the two have a long conversation, with Lazarus noting Luka to be similar to his father, Marcellus, as well as Luka’s fighting ability and their ideals of fighting for others, with Lazarus telling Luka that he will soon realize that coexistence between humans and monsters is impossible. Lazarus then leaves, telling Luka to follow suit once he’s finished with his orange juice. Afterwards, Luka suddenly realizes that Lazarus deposited another bomb within the bar, and it blows up, although none of the monsters seem to be harmed. Luka then asks Alice about self-righteousness and she merely tells him that it is just words, renewing Luka’s oath.

Chapter 2
Luka soon heads to the Bird God Shrine where the Garuda Girl’s Egg is located, however it is missing. A nearby Ilias Kreuz member named Lupton skulks and Luka forces him to reveal that his comrades discovered the egg a few days ago and carted it off to the organization’s headquarters. Alice says not to worry - the egg can’t be destroyed by human hands. Luka then marches off to get it back, but Alice seems worried - not about the egg, but because of Luka’s attitude, given his own history with the organization and his father’s role in it.

Luka heads to Gold Port, the organization’s base of operations, commanding the guards to tell Lazarus that Marcellus’ son wants to talk with him. He finds Lazarus standing next to the stolen egg, wondering how to destroy it. Lazarus comments that Luka’s just like his father; they both like to go charging into things without thinking. He asks Luka if he’s here for revenge, which leaves Luka a bit confused, but he assumes Lazarus is trying to recruit him. Lazarus reveals that Marcellus was not slain by a monster; Lazarus himself was the one who killed him. Marcellus went soft in his hatred of the monsters, and eventually started shielding them and had to be punished for betraying the ideals of the organization he created. Luka’s still trying to come to grips with this when Lazarus reveals that he and Marcellus were two of the four heroes who killed Alice’s mother. When Alice went berserk immediately after, she killed their two companions, one of whom was a woman who they both loved. In their grief, they founded Ilias Kreuz to take revenge, and Lazarus clearly bears deep scars from seeing his love torn apart before his eyes: coexistence is impossible when the other side has the power to inflict such horrors upon them. It’s easy for a strong hero like Luka to preach his high-handed ideals, but the rest of humanity is weak and afraid.

Alice walks in and interrupts Lazarus’ ranting, but it only takes a minute for him to recognize her face. She tells him that she shares her mother’s hope for peace, but Lazarus isn’t hearing it from the monster who murdered his companions - in his eyes, anybody who lies down with a monster is betraying their memory, and that includes Luka’s father. Luka finally snaps and draws his Iron Sword, holding it to Lazarus’ chest. Lazarus yells to go ahead and kill him, he’d rather die than turn back now. Regardless of whether Luka decides to drive the blade in or not, Alice stops him from doing so at the last second; seeing that Marcellus' son is unwilling to kill him, he turns to face the Monster Lord and tells her about what her mother said in her last dying moments, then she happened upon her deceased mother and ruined what they were about to set out to do in order to set things right between humans and monsters. Given all Lazarus has been through already, he taunts her by telling her that he's from the group killed her mother and says that she should certainly hate him for that and she should just kill him already to avenge her mother by killing the ones responsible for her death, she notices that he's intending to be a martyr and instead of killing him, she turns him to stone instead with her magic. Two Ilias Kruez members walk in and immediately flee upon noticing their petrified leader. With that, Ilias Kreuz is leaderless and dissolved.

Chapter 3
By the time Luka rebels against Ilias and she declares war and sends her assault force to Gold Port, Lazarus recovers from his petrification status while remembering the day he killed Marcellus. Heading out, he sees a Trooperoid attacking the town, and rushes to defend a boy out of pure instinct, but is easily defeated. Lazarus flashes back to his motivation of defending people; others rooted him on when they needed him the most, and he needed the motivation to start fighting for others. Lazarus then tricks Trooperoid into not firing her charged-up gun, saying that she would lose her footing due to nothing stopping the recoil, and then throws sand in her face, temporarily blinding her and causing her to swing randomly. However, Lazarus's efforts are all in vain when the boy suddenly comes out of hiding and wanders right into Trooperoid's range, causing Lazarus to push the boy out of the way and take the fall. Feeling his demise, Lazarus recalls the event to be similar to when he protected someone from Scorpion Girl long ago, and Marcellus jumped in to protect them. However, just before Trooperoid can finish Lazarus off, her gun is suddenly knocked away; Lazarus believes that he was saved by Marcellus, but instead it is his son, Luka. Lazarus asks him that if Ilias truly decided to end the world, but they quickly turn to more pressing matters.

After Luka defeats the chimera, more Trooperoids arrive to reinforce. Lazarus confuses by telling them who should be the one to rape him, then requests the aid of Salamander from Luka. Luka is confused, but Salamander appears because it directly concerns her and questions Lazarus about the matter. He tells her that he has a bit of experience of wielding the flame as Merlin imbued him with low-leveled fire spells, but she warns him that she is no low-leveled spell; Lazarus agrees to form the temporary contract with her and uses the flame to defeat the Trooperoids while Luka deals with the leader behind the attack, Assassinroid.

After defeating the chimera leader and thus causing the attacking force to withdraw, Luka turns to Lazarus, finding him charred. Salamander explains that he was burned from the inside out because he did not form an official contract with her, and she had no right to trample on his request as he was prepared to die. Lazarus' final request was to be buried right next to his best friend, Marcellus. After honoring his wishes and paying their respects, Luka and Alice vow to avenge Marcellus and Lazarus by defeating Ilias and ending her genocidal campaign.

Lazarus's sacrifice later unites the former members of Ilias Kreuz to fight against Ilias and ally with the other monsters defending Gold Port. Once Ilias is defeated, the former members swear not to reform the terrorist organization, as they say that it's dead, alongside with Lazarus' life.

Trivia

 * The real Lazarus is the subject of a prominent miracle attributed to Jesus in the Gospel of John, in which Jesus restores him to life four days after his death.
 * Regardless of Luka's choice to "Thrust" or "Stop" his attack aimed to kill Lazarus, it has no impact to the story.
 * According to Torotoro's blog, after Lazarus's death, the villagers constructed a statue of him, albeit a less accurate depiction in favor of handsomeness.