Various Anime Yandere One-shots.

Yandere! Forest Guardian! Midoriya Izuku

Izuku liked being a guardian, he really did, but it got really lonely. The only living things he ever saw were animals, and although they were definitely cute he wanted something more. He wanted someone he could talk to, share his day with. Sure, he spoke to the animals but it's not like they spoke back to him.
In short Izuku's life was pretty lonely and sad.
So imagine his surprise when a human girl visits him, or rather his forest. This was a rare occurrence, a human entering the forest that is. It was dangerous, or at least that's what the humans told themselves. No human in their right mind would ever try to enter.
Well, he guessed this human was odd then.
She looked rather... scared. Not of the inside, but of the outside. Izuku felt bad but he had heard that humans react violently to things they didn't understand. He had to take care of this place so he didn't want to take the chance of dying. But she looked so scared, wondering around the forest, her hands pressed against her chest. He was following her, but only because he was curious!
Then she saw him.
It was completely impossible for a human to see a guardian, it just never happened. But she did, she saw him and she got startled. It wasn't like he was a scary looking guardian. He had pointed ears and lime green eyes, but aside from that he looked nearly human. Maybe she could sense that he wasn't like her? He wasn't sure but he knew he had to calm this girl down before she had a panic attack the size of Kaachan's ego.
"Hey, it's alright, I'm not going to hurt you."
She went on to say she wasn't scared of him, but the horrible villagers who wanted to kill her. Izuku understood. She was different from other humans, but she wasn't aware.
That day Izuku promised himself he would protect this girl at all costs.

~~~

She wanted to leave. Why did she want to leave? He had been taking care of her, he had been loving her. They were getting along so well, he was almost sure that she loved him too! So then why was she trying to leave him? He didn't understand and for once in his very long life he was angry. He knew nearly everything about her, she was sick. She said she was dying.
That was fine, time stops in the forest. She won't be able to age or die there.
'I don't want to live forever.'
Too bad.

^^^
Next up is Vampire! Bakugou