When you want to add a new city to your kingdom, you'll need a City Deed to do so. City deeds can be obtained by completing quests or buying them directly from the store.
The requirements per deed
2nd City deed
To complete this quest you'll need to have 10 friends playing K.o.C. Usually people within alliances are quite helpfull to add their fellow players to achieve the quest or for appointing knights
3th city deed
Attack wilds from level 5 to level 8 in order to obtain; 4 sir Bor's crest, 2 sir Ector's and 1 sir Kay's crest.
4th city deed
Attack wilds from level 5 to level 8 in order to obtain; 4 sir Kay's crest, 3 Sir Bedivires and 1 sir Gawains
5th city deed
Attack wilds from level 5 to level 10 in order to obtain; 4 Sir Percival's Crest, 3 Sir Galahad's and 2 Sir Lancelot Crests.
6th city deed
Attack wilds from level 8 to level 10 in order to obtain; 4 King Arthurs Crest, 3 Morgana seals and 2 Mordred seals.
7th city deed
Attack wilds from level 8 to level 10 in order to obtain; 4 Stag King Seals, 3 Pendragon Seals and 2 Lady of the Lake Seals
8th city deed
Morgana has summoned Dark Forests to Camelot, which have corrupted mighty cities. You must prove to King Arthur that you are worthy of reclaiming a city from such a powerful force. You will need to acquire 4 Merlin's Seals, 3 Aetherseals, and 2 Ysbadden Seals by conquering Dark Forests. Then you can complete this quest to earn a Fey City Deed. You can also buy an Fey City Deed directly from the Court section of the Shop. You have to hit Dark Forest to recieve seals for city 8
You can find detailed requirements here http://koc.wikia.com/wiki/Fey_City_Requirements
You recieve 1 sacred Inspiration for completing this quest.