From the angle Tuba was observing from, it was hard to clearly define what that was. According to him, the world itself could be perceived from multiple angles, and the human living area was just one layer of it.
At the same place, looking from different angles could yield entirely different entities. For example, Hope Island was an island in reality, but from Tuba's angle it appeared as a giant atmospheric creature formed from white clouds.
According to Tuba, that angle was tentatively named the Great Tree, and it was feasible to attack the Central Computer from within the Great Tree.
This was not because he could influence the outside world from within, but because Gods themselves were very "heavy". Reality alone could hardly bear their weight, so their bodies would overflow into other dimensions.
