The Kyousou Giga Pilot video contains completely original footage before the premier of the ONA and TV series.
The OVA series type is reserved for episodes that are released independently from TV series or movies. This contrasts with the Special type, which is reserved for extra episodes that are released alongside TV series, movies or OVAs.
DVD/Blu-ray specials and introductory animation (pilots, prologues, episodes 00) which contain animation/voice acting not used in the parent show.
This has been denied multiple times, under the assumption it does contain animation/voice acting used in the parent show. It doesn't.
A small incident causes a young girl, Koto, to wander into this world.
She runs into a mysterious monk, gets chased around by a tech-obsessed girl, and heartily enjoys her chaotic and colorful new life, but meanwhile, out of sight, a certain plan is being set into motion...
In this mysterious city where spirits and humans have been thrown together, the festivities are about to begin!