I Became the Contract Beast of the Dragon-Proud Hero

On the first day after An Sen transmigrated, he found himself in the middle of a disaster. The original owner had just been rejected by the contract beast bound to his soul, stripped of his status as the duke's son, and driven to the empire's remote borderlands to die in a desolate place. The original owner killed himself in despair, leaving An Sen, who had transmigrated for no apparent reason, with a pile of messes to clean up. This godforsaken place had nothing but a bunch of yapping kobolds and goblins that ate anything. Worse, a giant dragon said to enjoy swallowing people whole was rumored to roam the nearby monster forest... But none of that was a problem!!! As a transmigrator who activated his System as soon as he fell into misfortune, An Sen firmly believed that, with his cheat powers, he was destined to follow the path of a mighty protagonist who would slaughter his way to the top! "Thirty years east of the river, thirty years west of the river. Never look down on a poor young man! Right, my System wifey?!" The head of the locals in this desolate place, rumored to swallow people whole, accidentally bound to someone's soul, not a giant dragon but a giant snake, Arzuka: I don't understand what he's saying, or what a System is, but he called me his wife! No, I have to make this little guy understand that he can't go around calling people his wife. In short, this is a story about an extremely possessive, steady, motherly giant snake seme and a lone-star, chuuni, domineering protagonist-style uke!!! Just another ordinary sweet little story. Also known as: I Accidentally Swallowed Someone's Cheat Power, So I Decided to Marry Him Theme: Snakes are the best