The Immortals

The Immortals is a secret organization formed by Alex. It is currently unknown when it was built, but soldiers of the Immortals always have their weapons prepared. They're also the creator of the Immortal's Sword (Which was upgraded to the Immortal's Energy Sword in Killing Dora - Legend of Alex OS) which Alex uses in battle.

In Killing Dora - Rampage of Dora OS, Dora threw a nuclear bomb at the temple, destroying it and shutting down the organization.

At the end of Killing Dora 666, the narrator secretly told the audience that there is a button that rebuilds the temple.