Sakamoto Ryouma, Wiki

Festival Portrait: Sakamoto Ryouma

Visiting Sakamoto Ryoma Memorial

Sakamoto Ryouma (Fate)

Conan & Kid's Battle For Ryoma's Treasure - Detective Conan Wiki

Ficha:Sakamoto Ryoma, Wiki

Sakamoto Ryouma Fate Grand Order Wiki - GamePress

Second Chōshū expedition - Wikidata

Zenderman - Wikiwand

Sakamoto Ryōma - Wikipedia

Sakamoto Ryōma, Fate/Grand Order Wiki

One Piece World Journey - Ochoku was a member of the Rocks Pirates (Wiki said so as well) All the Rocks member are inspired by real life pirates, navies and privateers.

The real Sakamoto Ryōma (1836-1867) : r/yakuzagames