"Give her back to me foul demon! Or by Ioun I swear I will destroy you!" Felix shouted.
He stood against this Pit Fiend in the decrepit underground temple. His sword was drawn and his holy aura glowed radiantly about him. The monster flew just out of his reach, hovering over Felix's head in the chamber's high ceiling. It taunted him with laughter before speaking.
"First of all," it started, "I'm an archdevil you ignorant mortal. Secondly, I have consorted with beings far more powerful than you. So I suggest that you save your bravado for someone more," it descended until it was nose to nose with Felix, "naive."
"I," he stuttered, "I do not fear you monster!"
The devil returned to the ground. It stood several feet taller than Felix and began pacing in a circle, as if eying its prey.
"You lie well paladin," the devil said, "but I can taste the fear, I can smell the anxiety, and I will gladly feast on both."
"Then fight me coward!" Felix shouted before swinging at the devil, his sword imbued with holy fury.
Before he could strike however, the demon teleported away and he struck nothing but the stone ground. The devil was already behind him and effortlessly backhanded him across the chamber. Felix jumped back to his feet and readied himself. The devil just casually strolled towards him.
"Now now," the Pit Fiend said, "none of that."
"What?" Felix asked, panting, "fight me!"
"I gain nothing by killing you. But I do have an offer," the devil said.
"I will not parlay with such an infernal abomination," he said defiantly.
"Really?" it asked, "not even for her?" it raised its left hand and conjured an ethereal orb. Felix could see a screaming human woman trapped inside.
"Svetlana," he whispered to himself.
"Yes, yes," replied the Pit Fiend, "I have no use for a weak scribe such as her."
It lept towards Felix and landed just in front of him.
"But a powerful warrior like yourself though," it continued, "that I could use."
"You want me to serve you?" he asked.
"Yes."
"And if I do so, you will release her?"
"Yes," it replied, inching ever closer, "but there will be some conditions."
"Like what?" he was disgusted that he was even considering this.
"You serve me. You do as I tell you or she'll die. You kill who I tell you, or she'll die. And you renounce your pitiful god or else, she'll die," the Pit Fiend said, "and then she can join you in eternal suffering."
Felix was about to answer when the Pit Fiend cut him off. "Oh," it said, "and you can never see her again. Or else she dies."
Those last words struck a chord in him. Would that even be worth it? She would continue to live but without him. Would it just be better for the two of them to suffer together forever? It sounded like some old, romantic tragedy.
No. No, he would not doom her to suffer at the hands of this monster for the rest of time. He swallowed his pride and buried his dignity before answering the devil.
"I will do it," he dropped his sword and shield and fell to his knees, "I will serve you."
"Of course you will," it replied, "you mortals are so predictable. What is your full name my new servant?"
"Felix Tetricus," he said.
"Do you pledge yourself to me and all my goals?" it began conjuring a spell and necrotic energy enveloped Felix from the bottom up.
"Yes," the devil's magic burnt away the holy symbol of Ioun on his chest.
"Do you renounce whatever ties you have to the mortal world, including the gods you served and the woman you loved?"
"Yes," as the spell continued his armor was slowly turned black as night.
"Now I just need to take something physical from you," it said, "in order to finalize the agreement." The Pit Fiend grabbed each of Felix's horns and burnt them away. Soon after there was an surge of dark energy around him and he could feel that every part of his body was immolated in unholy fire. Not even his infernal resistance could dull the sensation. He screamed in pain and fell on all fours, gasping for air.
"Now rise my herald," the devil commanded.
He slowly stood, carefully touching the singed stubs that used to be his horns. His armor gave off a new, dark aura and he could feel his skin crackle with necrotic power. He looked up to his new master and made eye contact.
"Yes...my Lord," he said, "now will you release her?"
"Of course," it replied, "I always uphold my side of a bargain."
It gave a toothy grin and held up the orb that contained Svetlana. It slowly dissipated from his hand and she appeared in front of them, frozen in place.
Felix approached her, stroking her face with his armored hand. "I'm so sorry."
The Pit Fiend waved his hand and with a shroud of dark energy, she vanished.
"Where have you sent her?" he asked.
The Pit Fiend conjured a scrying orb and showed him Svetlana in the forest back above ground. She frantically looked around shouting something, presumably his name.
"She'll live, just as I promised," it said, "now take up your weapon, oathbreaker."
That word sent a rush of guilt through him. He had fallen. However he quickly cast the feeling aside. Svetlana would live. That was all that mattered. He retrieved his sword and shield and felt that even his blade now glowed with dark magic.
"What do I call you?" he asked the Pit Fiend.
"Well I am the former and rightful Archdevil of Avernus, Warlord of the First Layer of Baator, hero of the Blood War, right hand of the Archdevil Zariel," it replied, "but you can just call me, Bel."
"Yes Lord Bel," he bowed his head.
Bel towered over him before placing a hand on his shoulder and saying,
"This is the beginning of a wonderful relationship, Felix, my Dark Templar."