What is the connection between manga, dori katana, and One Piece?

It's quite unique. In One Piece, katana often play a significant role and are closely intertwined with the manga's action and adventure elements.

It's possible that One Piece Ultimo manga shares a common universe with the original, or it could be a prequel/sequel exploring different aspects. Could also have callbacks or references to the main story.

I'm not sure there's a direct connection. Maybe Tomo is a character in a related spin-off or fan work, but not in the main One Piece manga.

Joyboy is a mysterious and significant figure in the One Piece manga. It's believed to have some crucial role related to the overarching story and the ultimate treasures.

I'm not sure there's a direct connection. Maybe bluebell is a character or element introduced in a special chapter or spin-off of One Piece manga.

The connection could be that Uta might be a new character introduced in the One Piece manga or have some significant role or storyline related to it.

Not much. Cadeau manga might be a completely different genre or series with no direct link to One Piece.

I don't think there's a direct connection. One Piece is mainly about adventures and pirates, not related to sunsets specifically.

There might not be a direct connection. One Piece is a long-running manga series, and Halloween is a holiday. Maybe there could be fan-made One Piece-themed Halloween costumes or events, but not an official link.

There's no direct connection. 'Tail' and 'One Piece' are likely two separate manga with distinct storylines and characters.