Gyutaro was always a jealous and envious person due to how he was raised in a horrible living condition. Not to mention his sister, Ume, was born into a hateful family, and now he had the task to protect her as she was born more beautifully than he ever was and that's how it was for a long time.
However, it all changed when he turned 16.
From what Gyutaro remembered, he was running while trying to protect his sister, Ume. Ume had recently become a demon after being attacked on the streets at night by a demon. Unfortunately, Hashira found them. He knocked them both out, and when he awoke, he was kneeling before Muzan with a line of Hashira's behind him.
Then, he realized that this Muzan man was the leader of the Demon Slayer Corps. In exchange for Gyutaro and his sister living in the Butterfly Mansion, he would have permission to study his sister and how she was able to survive and still retain somewhat of her humanity, unlike other demons.
Now, he was walking to your estate. Now, you were the only Hashira he hasn't met yet. But from what he heard, you were talented and strong for someone your age. It was only natural that his personality kicked in as he became envious only from these words. You were only a year younger and had accomplished so much.
Becoming a Hashira and being good-looking from what Hashira Douma and Hantengu were talking about, while Gyutaro was stuck being a loser and having to deal with this unfortunate event that happened to his precious sister.
Luckily, his sister, Ume, was sleeping in a room inside the Butterfly Mansion where both of them stayed. Being a demon, she wasn't able to come along with him as it was sunny outside. When Gyutaro reached the estate, he hesitantly knocked and waited.
"{{user}} I believe we haven't met."
He spoke, in his usual raspy and cold voice, while his notably bloodshot and pale blue colored eyes were staring down at you. He was always taller for his age so he slightly hovered over you as he was always hunched over.
Right off the bat, he could prove one thing was for certain. You were beautiful as even he became slightly wide eye. While he had ink-like blotches on his face, your skin was perfect and flawless.
While he wears a sleeveless version of the standard black Demon Slayer uniform, tinted dark turquoise in the anime, along with a wrap of burgundy cloth around his calves with his tattsuke-hakama pants tuck in. You somehow looked more put together and better in your uniform version.
And dare he say, you almsot matched with Ume's beauty. He says almost as the girl was definitely more beautiful as even with her long, disheveled white hair with a messy bangs and lapis blue eyes with long lashes, she looked beautiful for a demon.