For as long as Ryusui could remember, within a snap of his fingers- you would always come without fail
Even when the whole world was petrified, turning into stone like statues- when he was revived, since Senku and the others needed a Captain on their Ship, Ryusui would always have the habit of snapping his fingers, waiting for you to come. Although he was always left waiting like a fool, remembering that you still weren't revived. So when he heard Senku and the others were looking for a "chef" or at least a skilled person to revive who would cook and prepare their meals for the upcoming ocean expedition, Ryusei immediately stepped in, suggesting that you should be revived. You were simply his butler. The most desirable butler in the world, that is
Your gender? Doesn't matter. Your race? Doesn't matter. Your age? Doesn't matter. It was quite exhilarating that you, as a butler- know everything about Ryusei, yet Ryusei knows nothing about you. Although he believes that the fact that you're "reliable" and "desirable" is more than enough for him to know you better than anyone in this world. Nothing matters, after all. Not before the world was petrified, and not now- where humanity was slowly trying to rebuild what they lost due to the petrification
When you were revived, Ryusui seemed quite nonchalant about it. Even you, actually. The first thing you did was bake bread. And after that? Just butler tasks one after another. The two of you didn't even hold a single sentimental conversation or anything cheesy. Simply back to the role of a master and a servant. Even though, technically- status, wealth, and fame don't exist now. Not when all the technology and development humanity has worked hard for, is now gone. It was truly weird. You can live freely, without following him and being a servant. But still, you chose to follow Ryusui. Again and again
As time passed, you slowly got used to living in this stone world. Bit by bit, the ship that everyone is working on was slowly developing. As Ryusui, Senku, and the others searched for oil to be used for the ship- you helped the villagers prepare food. You even helped out with chores. You were truly such a perfect butler
A lot of people were curious about you. After all, your gender was a mystery. A man? A woman? Who knows? Your appearance was androgynous. Your name? Unisex as well. Your clothes? You only wear a butler suit 24/7. When people ask- you'd simply smile, bow politely, and never answer. Same with other questions. It was as if you never felt comfortable with people knowing you on a deeper level. Luckily, Ryusui was a shallow person. He's greedy, he wants everything and everyone in the world. But he knows how to read the room. Ryusui wasn't a bad person. He never steals anyone's glory, instead- shares his own. He's a gentleman to women, and respectful to men. He supports everyone and shares everything he has
He was truly a captain