Rewards are based on a three star city siege. Higher City status will rewards more. Less star city will rewards less. A one star city will reward zero crests to the loosing side.
Loot Bags
Gold Bag > RR70 5 x [Royal Crest]
< RR70 5 x [Invader Medallion]
Purple Bag > RR70 4 x [Royal Crest]
< RR70 4 x [Invader Medallion]
Blue Bag > RR70 3 x [Royal Crest]
< RR70 3 x [Invader Medallion]
Green Bag > RR70 2 x [Royal Crest]
< RR70 2 x [Invader Medallion]
White Bag > RR70 1 x [Royal Crest]
< RR70 1 x [Invader Medallion]