To upgrade your Arcane Sanctum, you need Ceremonial Chalices.
With each upgrade, you need more Ceremonial Chalices.
Below is a list of possible ways to gain these.
Gems
You can purchase Ceremonial Chalices using gems.
1 Ceremonial Chalice = 15 Gems
10 Ceremonial Chalices = 125 Gems
100 Ceremonial Chalices = 1,154 Gems
1000 Ceremonial Chalices = 10,000 Gems
Campaign Elite Sweeps
You can sweet elite campaigns to pick up extra Ceremonial Chalices.
Elite 2-1
Elite 2-2
Elite 2-3
Elite 2-4
Elite 2-5
Elite 2-6
Chests
Chest from the VIP daily clan gifts (Sunsingers city) gives Ceremonial Chalices too.
VIP Daily Clan Gifts
You can collect 5 Ceremonial Chalices per gift from daily VIP Clan gifts (Once you have level 25 diplomacy for this city).
Regular Events
Every 3 hours, you can do a regular event (Have to complete only the first stage of it).
You gain 20 Ceremonial Chalices each time you complete it.