A shrine that moved in from the outside world. Fearing that people were losing faith in the gods of Moriya Shrine, they chose a future full of potential over the fading glory of the past.
Kanako's trademark shimenawa represents an entwined snake. Why a snake, you ask? Well, snakes can molt their old skins and be born anew, which makes them symbols of revival, rebirth, and eternity.
Why did Moriya Shrine come to Gensokyo? To regain faith. Kanako and Suwako used Sanae's powers to gather faith from humans.
In another Gensokyo, you might have met Sanae first and ended up in the care of Moriya Shrine instead. Perhaps you would have helped them gather faith as you tried to find a way to return to your original world...
When the rumor of Seal Crystals reached Moriya Shrine, you would have gone to Hakurei Shrine with Sanae. There, you would have been able to see Reimu get angry at Sanae as usual. You would also hear for the first time that outsiders who went to Hakurei Shrine would be able to return home...