So lets collate what we know about these little bilge rats
As far as I am aware it does not cost you an AP to attack someone with an orb
: Free Gold OR lose gold
: Free level 2 unit
: Free level 1 unit
: Free AP
You may steal a maximum of 3 orbs each day regardless of the orb's colour. You may only have one orb at time. If you have had your maximum quota of orbs for the day you will be unable to hit warlords who have an orb. If you have an orb in your possession you will be unable to hit warlords who have an orb. Some orbs are invisible until you hit the warlord who currently owns it - then you own it and it remains invisible to other warlords.