Once a week all players in a clan will have the time-limited opportunity to gather SHARDS for the Clan Box. Collecting shards upgrades Clan Box to a higher level. The higher the level, the better the reward.
SHARDS is a special resource, that is required to level up Clan Box. Shards can be earned in regular arena battles during this event.
Once the event has elapsed, all clan members get Clan Box of the same level.