After Uta agreed to set sail with Gray and his companions in the plaza, Gray held a joining ceremony for her.
As the paint-stamped seal came down, Uta clasped her hands behind her back, leaving a pink Fairy Mark on the back of one hand.
His name was Gray, and he had founded the Fairy Tail guild. How could it not have a symbol?
So Gray had already stamped every member with a joining seal.
Although this world had no magic, it had all the dyes they needed.
Using the sort of pig-branding stamp technology Gray's hometown had back in his previous life, combined with this world's remarkable dyes, they could make a mark that stayed with someone for life—harder to wash off than a tattoo.
Having accomplished his goal, Gray didn't rush to set off. Instead, he began testing Uta's abilities.
"Uta! What does your Devil Fruit ability do?"
"Guild Master, my ability is simple. After someone hears my singing, I can draw their minds into a mental world of my own creation." Now that she'd decided to join the guild, Uta understood that they needed to learn about one another's Devil Fruit abilities so they could coordinate in battle.
Hearing that, Gray immediately said, "Try it on me first!"
"Okay!"
As Uta activated her ability, Gray hadn't even noticed when the world around him changed.
Everything in this world was bright and colorful, filled with a little girl's fantasies.
Gray had no time to pay attention to any of that. He immediately began testing his own abilities.
"Armament Haki: full-body hardening!" In an instant, Gray turned black and purple.
"Cannon Fist!" He gathered all his strength in his right hand and punched straight ahead.
Boom!
After a tremendous sonic boom, Gray surveyed his surroundings. "Looks like even an