"Riverbed Soul Saver" is a Touhou fangame whose script was written by Ido and Len. The first demo version was released on March 24, 2014, and the second demo on April 25, 2014, adding Marisa as a playable character. The full version with 6 main stages was released on June 27, 2014 and next major update on September 15, 2014 added an extra stage and Futo as a playable character. The update on January 31, 2015 added a Phantasm Stage and an Overdrive mode. The game is a sequel to The Last Comer and Mystical Power Plant, and thus has some references to them.
After the events of the previous games, there has been an influx of newcomers to Gensokyo. Fearing that the Great Hakurei Barrier will be put under too much stress, Yukari has expanded the interior of the barrier in order to delay new arrivals. Now, a massive amount of something is approaching the barrier, bringing a cold front with it. Reimu, Marisa, and Futo are sent out to the barrier's "Otherworld" to investigate, and deal with it before it becomes a threat.
This game contains examples of:
- Anchors Away: Takenouchi no Tarumi throws giant anchor danmaku.
- An Ice Person: Ruri, a bug youkai and former shikigami. Her name implies that she is connected to Rlim Shaikorth, a giant white worm that blasts landmasses and ships with extreme cold.
- And I Must Scream: Momohime was sealed in her own castle by the Fujiwara clan and sunk deep into the ocean, with no way to escape or get inside. She was trapped there for centuries until Tarumi's intervention.
- Beethoven Was an Alien Spy: Several cases.
- Suitenguu no Himemiko is based on Emperor Antoku, the 81st emperor of Japan, who was drowned as a child in the battle of Dan-no-ura. According to this game, he was actually female and didn't drown to death, she was simply spirited away by Momohime.
- Also, the famous omnyouji Abe no Seimei was killed by a snake youkai who absorbed all his powers and memories. And he happens to be Ruri's master.
- Yamatoyo no Momohime is Queen Himiko's daughter.
- Bifauxnen: Takenouchi no Tarumi. You'd be forgiven if you thought she was a he.
- Butterfly of Death and Rebirth: Suitenguu no Himemiko has a Battle Aura shaped like butterfly wings.
- Cool Shades: Yamato no Yato is the only one so far in any Touhou game, fan or otherwise, to be seen sporting sunglasses.
- Divine Parentage: The shrine maiden Hatsuna Magatsuji is distantly descended from Mitama Magahara, from Mystical Power Plant.
- Also, Tarumi is revealed to be Tojiko's ancestor.
- Expy: Abe no Kiyohime is basically an expy of both Mima and Yukari, looking visually similar to Mima, while having an overdrive spellcard based on one of Yukari's. In addition, she also controls shikigami.
- Red Eyes, Take Warning: Yamato no Yato normally has Eyes Always Closed, but when she's feeling particularly smug or devious, she opens them up. Also falls into Glowing Eyes of Doom.
- Token Mini-Moe: Suitenguu no Himemiko, who looks like a little 8-year-old girl. She is also based on Emperor Antoku, the Grandson of Taira no Kiyomori and also 81st emperor of Japan, who was drowned as a child in the battle of Dan-no-ura.