The Clan Castle is arguably the most important defensive structure in Clash of Clans. This building can store units that will defend your base from enemy attack. Given that many units in Clash of Clans deal far more damage than your towers, the Clan Castle can be the strongest building you have on defense.
The Clan Castle also holds the loot rewards earned from Clan Wars.
After a Clan War, your reward is automatically stored in the Clan
Castle. It is not transferred into your normal storage structures and
available for spending until you select the Clan Castle and select the
“collect loot” option.
Clan Castle Upgrade Levels by Town Hall Level
As the Clan Castle increases in level, both its unit capacity and
Clan War loot capacity will increase. As a result, it is important to
keep your Clan Castle upgraded as you level up your Town Hall.
Note that the Clan Castle’s units can only be given to you via
members of your Clan. Clan Castle units are all considered “donations”.
One of the primary extrinsic motivators for joining a clan is to be able
to receive units from clanmates in the form of donations. Note that
donating units provides the donating player with credit towards an
achievement along with a small amount of experience points based on the
unit donated.
Clan Castle Strategy
The Clan Castle is one of your best defensive structures (if not the
best defensive structure), but only when used appropriately. Below we
will discuss the types of units you should try to get in your Clan
Castle, where to place your Clan Castle, and the relative importance of
upgrading your Clan Castle in comparison to other structures.
Unit Choices
The Clan Castle is only as good as the units inside of it. Of utmost
importance is to always keep your Clan Castle stocked with units,
particularly if you are holding a lot of resources. A fully-loaded Clan
Castle can literally be the difference between losing nothing and losing
everything in an enemy raid.
For the purpose of cheap defensive units, Archers are the best bet.
They are moderately effective due to their ability to shoot over walls.
They also have solid DPS, making them good Clan Castle units. The
biggest weakness of the Archer is that they are easily taken out by a
Lightning Spell. Archers are also very weak when lured away from the
base.
If you are in a clan that is willing to donate more expensive units
or if you have an alt account, there are better options than the Archer.
In particular, Wizards as well as the Dragon make some of the best Clan
Castle units. Wizards deal great damage (and deal area of effect
damage), while Dragons also deal area of effect damage, are flying
units, and are difficult to kill (a Lightning Spell is not going to cut
it).
Note that the Clan Castle can also be used for offensive purposes,
especially for war battles. Trading powerful offensive units with
clanmates or passing them along from an alt account can improve the
strength of an attack significantly. One player donating a Golem (if
high enough level), Hog Riders, Balloons, or a Dragon can significantly
improve the strength of your attack.
Clan Castle Placement
Clan Castle placement is not terribly important before Town Hall 7.
At Town Hall 7 and beyond, placement becomes very important. Players
tend to neutralize the Clan Castle’s units by using a unit or two to
pull the units out, then drawing these units to the corner of the base
where these units are then summarily destroyed with little loss. At Town
Hall 7 and beyond, players have enough buildings where it can be made
difficult to lure out Clan Castle units.
In order to prevent Clan Castle units from being lured out, the Clan
Castle must be placed in the center of the base. You can see the Clan
Castle’s trigger range by selecting the Clan Castle and viewing the
white circle. Make sure there is no drop zone within the white circle,
and try to place buildings along the perimeter of this white circle to
prevent enemy units from easily triggering your Clan Castle units.
Clan Castle Upgrade Priority
The Clan Castle should be considered amongst your higher upgrade
priorities. Increasing its capacity will significantly improve your
defensive strength. However, it is not your number one upgrade. It is
usually a better use of builders to grab brand new structures and
buildings while focusing upgrades on the Laboratory. Imagine the Clan
Castle as the strongest defensive tower; it should be upgraded first
before you upgrade any other old towers, but upgrading other structures
and setting up an appropriate base layout for your new Town Hall level
takes precedence.