Current Citadel Unit Rules:
1st time capture - 0 times defended= 10k units
2st time capture - 1 times defend= 20k units
3rd time capture - 2 times defend = 30k units
4th and all next capture = 30k units at any time

Citadel units could be hired in those amounts ANY time during Order owns Citadel.

Note! Any player who will be noticed to join Order who own Citadel of any type, hiring units, and return to own Order - could be baned at game up to 7days! Especially if it would be done by entire Order and units used in next Citadel round or city/location capture! In such case Citadel/location/city would be removed from captured Order.