As the Sect head and the Grand elder tried to access the Space gate for that Island they realized that they couldn't do so.
The Space gate was blocked from other side.
They widened their eyes in shock and horror as they understood the implications of this happening. By the time, they decided to come and see the situation themselves, their island seemed to have been captured and they already suffered some serious losses.
The captured Island have Space gates connected to the main island of the sect and some other places where people of higher-levels might stay.
That is for the easier inspection of things. There almost eight islands surrounding this one with various resources. This one-third of the Usaine sect's foundation.
Once this captured, it would be almost impossible to evade the capture of the remaining islands.
