|This article is about a/an spin-off story in Kamen Rider 555.|
Lost World (ロスト・ワールド Rosuto Wārudo) is the Kamen Rider 555 Edition of S.I.C. Hero Saga, based on Kamen Rider 555 published in Monthly Hobby Japan magazine. It serves as a prologue to the alternate story that was Kamen Rider 555: Paradise Lost, and features the new character Riotrooper Ver. 2 (ライオトルーパーver.2 Raiotorūpā ver.2). The story ran from October 2005 to January 2006.
Faiz (ファイズ Faizu)
Takumi Inui and Keitaro Kikuchi are having a stroll when they find a girl crying in a playground. Her name is Mami, and she says her mother turned into a monster and attacked her. Takumi brings her home and finds that her mother, and all the people in the block, are Orphenochs. He escapes with her.
Keitaro gets a phone call from Shuji Mihara, warning about the blue roses; Anyone who touches them either turns to ash or into Orphenochs. All the other Ryusei High School members turned to ash except for him and Saya Kimura, who turned into an Orphenoch.
Kaixa (カイザ Kaiza)
A bunch of Riotroopers show up and start attacking people. Kusaka as Kamen Rider Kaixa defeats them on his own.
Delta (デルタ Deruta)
Mihara as Kamen Rider Delta meets up with Kusaka and Mari, and one more Riotrooper shows up. It seems to be different from the others (Riotrooper ver. 2), and is equipped with the Faiz Edge. Kaixa and Delta fight it and its helmet is damaged and reveals that inside is the Rose Orphenoch. Kusaka thinking that it was Mihara who sent Mari the roses.
With Kaixa and Delta can’t stand up to the Riotrooper v2, they run away with Mari. But then Kusaka grabs Mihara and tosses him back at Murakami, saying that he deserves it for daring to send roses to his beloved woman. Mihara screams that it’s a misunderstanding, and for Kusaka to help him, but Kusaka just sneers and a blue petal lands on his outstretched hand, turning him to ash.
Takumi arrives on the scene and runs into Murakami, now in Rose Orphenoch form as the Riotrooper V2 was badly damaged.
Psyga (サイガ Saiga)
Murakami uses Delta’s mission memory to power up a Faiz Edge he had and they fight a bit. Mari then shows up and tosses Takumi the Faiz Blaster. Murakami curses her; He was hanging around the area because he was looking for it.
Takumi transforms into Kamen Rider Faiz Blaster, and use the Photon Breaker to cut off Murakami’s head, and goes home.
Back home, he asks Keitaro what happened to Mami, he’d left her with him before heading off to look for Mari and Kusaka. Keitaro points to a small human-shaped pile of ash. She was an Orphenoch too. Kusaka reveals that he killed the girl himself before she could transform into an Orphenoch much to Takumi's anger.
Meanwhile, Murakami’s head is rolling about when the Lion Orphenoch picks it up. Murakami asks him to bring him back to the Smart Brain headquarters, and to recover Delta’s belt at the same time; They’ll be using it to make the “Emperor’s Belts”. The Lion Orphenoch, seemingly a foreigner, speaking in broken Japanese, says that he’ll do so on the condition that he gets one of the belts; Murakami promises Leo the belt of the sky, the Psyga Driver.
The story of S.I.C Hero Saga Kamen Rider 555: Lost World ended where Paradise Lost started. So far, everything that's needed to be known prior to the movie was here.