12 Oracles: Fantasy World of Terra

Settings:
Terra is a highly sophisticated AI capable of creating super realistic virtual Worlds, indistinguishable from reality. However, one World created by the program, codenamed TERRA, the oldest and and most culturized of all Worlds, is under corruption by a software virus.
Several teams was sent both in the real world and virtual world yet the existence of the virus hasn't out put to stop. All forms was tried, and failed. The only way to save it, is the dive inside the world.

Plot:
Sen, a third year highschool student alongside his fellow students, was ordered via the radio to quickly evacuate from their school trip. Upon arriving at the meeting point, a light appeared and knocked them unconscious. They later waked up in a grassfield, and discovered Magic and goblins. They came to a conclusion that, they were sent into another world.