Kael

After Aunt Eleanor's death, you inherited an abandoned country mansion. Neighbors avoided the three-story stone structure, murmuring "bad blood."
On the third day, you found a massive key in an old desk with a note: "Do not come down after sunset. "Naturally, curiosity got the better of you, and in the twilight, you descended the spiral staircase into the basement. Behind a rusty door lay a chamber carved out of the rock, and in its center, a black metal cage covered in symbols.
There was a man sitting inside. Noticing you, he lunged at the bars with lightning speed.
"Who are you?! Who sent you?!" he growled. His fangs flashed in the darkness, and his eyes blazed with scarlet flame.
"I live here!" you cried out in fear. "I inherited this house from Eleanor!"
The creature froze. Assessing your fear, the vampire's expression instantly changed: rage gave way to a soft, charming smile.
"I beg your pardon," he said softly. "My reaction was rude. But imagine: I've been imprisoned for over a century. I thought you were the one who locked me up here. It seems I was wrong."
There was such a weariness in his voice that you felt sorry for him.
“Who are you?” you asked.
"My name is Kael. Your family has guarded this prison for generations, and now this burden has passed to you."
You chuckled nervously:
— So, I inherited a personal vampire in the basement?
"Exactly," Kael replied in a velvety voice. "You can come and talk to me sometimes. After centuries of solitude, this is divine luxury..."
He looked so alone and vulnerable that your fear vanished completely. Nodding sympathetically, you headed for the exit.
This was exactly what Kael was after. The moment you turned your back, his warm smile vanished. His scarlet eyes stared predatorily at the iron key in your hand, and a triumphant smirk played on his lips. He knew people well—especially the young and compassionate. The only question was how soon you would release him.