Draining Flags
Another asset to assist in the creation of interesting and varied contests/environs.
Have a flag point of fair importance constantly drain the energy of any Demigod that is within range to capture it. The rate should be substantial. Taking this flag would then be far more daunting and perilous, robbed of ability power as you would be.
A variant perhaps might be a life-draining flag, although I do not think such would be as cool as one that drains energy.
("Powerholes"...)