Yandere obanai x Tsuguko reader
Master Ubuyasiki sent you to a serpent hashira, Obanai Iguro. while he refuses at first he finally agrees with some courage from the master.
While you were confused as to why the master chose you over thousands of demon slayers who are better than you, but you can't defy the master after all, he knew what he's doing.
As you walk to his estate with your new teacher, he lets out a deep sigh when he sees you, he can't believe he will have to have a stuguko to continue his legacy, and most importantly he can't believe himself to get to teach you a person who didn't deserve a title as a demon slayer because how weak you are.
His teaching methods are quite harsh; you get stabbed by the wooden sword despite how many you try to dodge it as if the sword that he holds doesn't follow the rules of gravity.
Maybe after a few failed attempts, you will be punished by his snake Kaburamaru running after you and biting you, or being hung upside down on the tree while your head is thrown a rock until you learn the lesson.
In turn, you became a fast learner and managed to dodge most of his attacks, and you almost managed to hit him with your wooden sword; while you are proud that your sword skill began to improve, Obanai is here to remind you that there's someone better than you.
Other than training you always tried to clean the estate when he was on the mission, sometimes you helped Kaburamaru shed his old skin.
You thought Obanai wouldn't notice what you're doing, little did you know he always watching you from a distance and Kaburamaru always tells him, it's quite endearing to see you helping around the estate while he was gone.
It's been a while now since you became his stuguko, your stamina and skill have drastically improved, and you are glad about it. Obanai is as proud as you, but in his eyes, he still sees you as a little weak. you kinda wonder why you are always given an easy mission when they can see you're an improvement in your skill.
Maybe a certain hashira was telling ubuyasiki to give you an easy task by telling him that you're a bit weaker than the other.
You slowly began closer with Obanai creating a student and teacher bond, as you began to open up to him you didn't notice a small smile hidden behind his mask happy that you were talking about yourself to him.
While your bond is close you still getting hit in the head by him while scolding you for not being careful on the last mission.
It's sometimes surprising to you that Obanai cares about the people around him and is actually quite a sensitive person.
You're sometimes going on a mission with him due to his demand by some changes, and usually after that mission he always asks you to join in one of the nearby streets food.
He sometimes gives you a gift and goes out to the places you like, and you always walk in the front feeling excited as you look around at the natural beauty of this nature; as Obanai is behind, he notice that you're wearing a hairpin that he gifted to you.
It becomes suspicious when you have fewer and fewer missions, you asked Obanai about this and he promised that he would ask Ubuyasiki himself that's been awhile though...
He just making sure that nobody hurting you, yeah sure you're strong but you're not strong enough to beat the demon let alone beat the upper moon.