Looking forward to your message, especially with the new event coming in New Clash of Knights Heroes ( 
Early Information on New “Clash of Knights” Alliance Quest [Part of The Beta Beat V42] - Gameplay Help & Tactics - Empires & Puzzles Community Forum (smallgiantgames.com)):
“Only those will able to play this quest who are in an alliance before the event starts.
The Epic and Legendary tiers are locked at the start of the event.
Epic tier is unlocked when your alliance reaches 2.5 million points in total.
Legendary tier is unlocked when your alliance reaches 10 million points in total.”