Manga / My New Devil Wife

14 year old Theo Asper has had a rough two years. Abandoned by his parents as a baby, he was adopted by a loving elderly couple. But they passed away around the time he turned 12, and he was left to fend for himself. With no real family, he couldn't find anyone to hire him and began working at the Mercenary Guild. Being small and weak, he works as support to mercenary parties by carrying their baggage, stripping monsters for materials, and other miscellaneous work. But the mercenaries he works for are rough and demanding, and blame him for things he has nothing to do with. After being kicked out of parties too many times to count he decides to study magic to gain power for himself. Inside a book on magic theory he stumbles on a devil-summoning ritual, and he learns that he can get Power at a Price. He studies what he can, but the information is vague enough that he isn't deterred despite the warnings. When he summons the devil Helvi he completely forgets his original goal and asks to be married to her instead. Helvi doesn't believe him at first, but sees in his heart that he is completely smitten with her. Theo, thinking he's being turned down, unintentionally charms her into agreeing with his wish. Thus a new couple was born.

This is a manga written by Shiryu and drawn by Tonari Keru.

Associated Tropes:

• Accidental Discovery: Theo learns how to summon devils when studying magic and finds the summoning ritual being used as a book-mark.
• The Bully: The adventurers Theo worked for as a porter prior to Helvi entering his life were initially happy to have him but quickly started blame him for their own shortcomings. Most never touched him again after kicking him out, some hurt him physically, and only one would reliably rehire him. Unfortunately that group was Carl and his party, who became accustomed to bullying him.
• Bystander Syndrome: The guild receptionists are all very fond of Theo, but all they can do is glare at mercenaries that abuse him because guild rules forbid them from interfering in inter-mercenary incidents.
• Cuckold: Carl and his crew think so little of Theo that they immediately try to borrow his fiance. Even after Helvi breaks Carl's arm, his two other party memebers get a group together to take Helvi by force. Too late, they realize that they're dealing with a Violently Protective Girlfriend who is far stronger than them all put together.
• Entitled Bastard: Carl and the rest of his three-man party. When Theo brings Helvi to the guild and introduces her as his fiance, Carl and his party surround him and demand he hand over Helvi. For his part Theo loudly refuses, expecting to get beat up. Carl learns first hand why actually trying to do it is a bad idea as Helvi takes offense and breaks his arm!
• Intimate Healing: Theo nicks his thumb when preparing breakfast. When Helvi notices, takes his thumb into her mouth and heals his wound. He's so flustered afterwards he doesn't know what to do with his thumb!
• Irony: The word Theo uses most to describe Helvi's awe-inspiring beauty is "angelic." She's a devil! In most mythologies, angels and devils don't get along and would see being named the other race as the highest insult. Helvi, for some reason, actually takes it as a compliment.
• Loophole Abuse: Discussed. Helvi states that most of the times she has been summoned the wisher would then flee after getting their wish, trying to avoid paying the price. She didn't let any of them escape.
• Marriage Before Romance: Helvi and Theo are married in chapter 1. The rest of the story is about the two of them learning how to be a couple and exploring each other's boundaries.
• Mayfly–December Romance: When Theo summons Helvi, she's already millennia old while he's 14.
• Nothing Personal: Helvi reminisces that she's killed hundreds of humans impersonally, often as the price for granting a summoner's wish. This is contrasted when Carl insults Theo by trying to cuckold him, and she realizes how long it has been that she personally wanted to kill someone.
• Our Demons Are Different: Helvi (despite being a devil) can, and does, pass for human when she hides her horns and wings.
• Parental Abandonment: Theo's parents abandoned him when he was a baby, and his adoptive grandparents passed away when he was 12. He had to grow up fast, and the only way to survive was to become a mercenary.
• Power at a Price: The way devils operate. When a devil is summoned, the summoner can make any wish he desires but had better be prepared for an equal compensation to be taken from him.

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