Extra bits meant to add to the Blue Seed story. Episodes 1-13 are extras shown on the video releases of Blue Seed in Japan. They take place after every other episode, such as Omake 1 follows episode 2. Episode 14 is an extra featured with OVA Blue Seed 1.5.

Momiji is an average girl until the day she finds she is the descendant of the great Kushinada family. Only she, with her Kushinada blood, can stop the Aragami, demonic plant-like monsters threatening to destroy Japan. Along to help her is the TAC, and a possible love interest in a young man named Kusanagi. (Source: ANN)

Ryouta Sakamoto is unemployed and lives with his mother, his only real achievement being that he is Japan's top player of the popular online video game Btooom! However, his peaceful life is about to change when he finds himself stranded on an island in the middle of nowhere, with a small green crystal embedded in his left hand and no memory of how he got there. To his shock, someone has decided to recreate the game he is so fond of in real life, with the stakes being life or death. Armed with a bag full of unique bombs known as "BIM," the players are tasked with killing seven of their fellow participants and taking their green crystals in order to return home. Initially condemning any form of violence, Ryouta is forced to fight when he realizes that many of the other players are not as welcoming as they may seem. Teaming up with Himiko, a fellow Btooom! player, they attempt to get off of the island together, coming closer and closer to the truth behind this contest of death. [Written by MAL Rewrite]

Venturing into the wilderness, the skeptical Ryouta Murakami and the ambitious Kuroneko were on a quest to prove the existence of extraterrestrial life when a tragic accident occurred, reaping Kuroneko of her life and leaving Ryouta in a critically injured state. Ten years have passed since the disaster, and Ryouta is now living a normal life in high school. He vows to prove that aliens are real in honor of his late friend. A transfer student named Neko Kuroha unexpectedly arrives one day, bearing a striking resemblance to the late Kuroneko—even sharing a similar name. Most mysteriously, she seems to possess supernatural powers. As Ryouta takes more interest in Neko, he is drawn into a deadly world where dangerous scientists hunt magic-wielding witches that have escaped from their secret research laboratory. Neko is one of these escapees, but there are many others who are in similar situations, and it's up to Ryouta to protect them from their would-be captors. [Written by MAL Rewrite]