So I saw the action "capture" - and read it can be used twice a turn, though is there anything else a capture can be combined with? - Seems like using capture once is a totally stupid (and weird it is possible) otherwise.
You can capture to make a hex from another Element Neutral. (example: you capture a hex from team water, that hex now becomes neutral)
You can then capture to make the neutral hex your own! (example: you capture the neutral hex, that hex will now be captured by your team)
Capture costs 2 AP so can be combine with a move action (2 AP also) the same turn. Team Underworld can capture to make hexes neutral, but they can't claim the ground for their team!