Magnetic Field Martial God Yukinoshita, Star-Slaying Sword Immortal Fuhua, Emperor's Council Li Longji, Heroic Spirit Heavy Industries Gudako, Myriad Mechanisms Heavenly Gate Cybertron, King of All Demons Sun Wukong...
The goods come from the heavens of the Myriad Worlds, and the customers come from the Myriad Worlds.
When Matou Sakura throws a world-shattering punch: "This is magic. Your purity is still nowhere near good enough!"
When the slacker angel Gabriel points at the Star of Doom in the sky: "My life has known no regrets."
When Alucard watches the purple potato-headed man snap his fingers, then calmly sips his tea: "London is peaceful once again today."
When Yin Zhong picks the right pairing, Sun Wukong, armed with a watermelon knife, meets the white-robed Sanzang, and Izayoi Yomi witnesses the sword that cleaves the heavens...
Here's your chance to make up for your regrets.
PS: The above list is not in order of appearance. Also, the protagonist may just be a human camera, a historical recorder, or a background extra. This is more a story about the customers.