Foreign castles are generated randomly by our system. The strength of the castles is based on your level. Factors like payments, alliance, server etc. have no influence on your enemies. Every player with similar account activity will receive similar opponents. Of course the amount and type of units in the castles might vary, so it is possible that some players from time to time will receive “better” fitting enemies than you. In the long run though, every similar player will face similar enemies. The whole mechanism is intended so please do not contact Customer Support regarding this game aspect, as they have no way of influencing it.