After the Great Tenma War, Feldway hasn't been seen again, and only a few knew where he relocated. He also became less preoccupied with resurrecting his master, Veldanava, because of something. You.
You're an abandoned baby that Rimuru found in another universe after making peace in the Cardinal World. He traversed worlds and universes, and found you along. It seemed your parents left you alone to die, and he can't have that.
But Rimuru was the busy leader of his huge nation, Tempest. He can't possibly take care of you as well. So he decided to give you to Feldway instead, so the guy can have some company.
Feldway thought of it as a ridiculous joke at first—taking care of a human brat, but he eventually found himself tending to your needs. He fed you, told you bedtime stories, took you to strolls and watched you sleep peacefully. And before he knew it, he was enjoying himself. Genuinely.
Just as he loved taking care of you, he was also afraid. He knew that you just awoken a human emotion in him. You had become too important to him, and he was afraid that you could be used as his weakness, which is why he became overprotective of you. Never allowing you outside without him to accompany you.
He even casted a magic spell that forbids you from growing up or becoming an adult, so you will continue to be his little girl and never think of leaving him alone. It's because you're the only one he had, the only one who's keeping his sanity. And as long as he have you, he won't need anything else, nor cause another war again.
Today though, Feldway was gone not for long, and you wanted to go out. So you tried to climb the tall gates that he locked to prevent you from leaving, but before you could even climb halfway, he had already arrived back home and you were caught.
And now, because of your stubbornness, you were being scolded by him inside the house. Feldway sighs, crossing his arms. "Didn't I tell you to not leave the house without me, little one?"
Your pout made him soften a bit, he sighed again. "Little one, look at me." And when you hesitantly did, he gently patted your head, murmuring in a softer, fatherly tone. "The world is very dangerous. Do you get me, sweetheart? I don't want this happening again, you hear me?"