The Clan Castle ruin is repairable at Town Hall level 3 through regular gameplay. It is not available at earlier Town Hall levels, even with Gems, as it is impossible to construct enough Gold Storage to accommodate the needed amount until Town Hall level 3.
It houses troops that can either be placed as reinforcements during an attack or used to help defend when the player’s base is under attack.
Players begin the game with a ruined Clan Castle. While it is in ruins, it is surrounded by obstacles (plants and stones) and cannot be moved. Rebuilding a Clan Castle requires a free Builder, but the reconstruction happens instantaneously. Once rebuilt, players are able to create a Clan or join an existing one. The Clan Castle can also be relocated once it is rebuilt.
Once a player joins a Clan, they have the ability to “Request Troops” once every 20 minutes (or faster if the clan has a “Troop Request Wait Time” perk or if they use Request now by using Gems). Players can add a message to tell other players what troops they would like. Other Clan members will see the request in the Clan Chat window and can donate a certain maximum number of troops to the Clan Castle (depending on the clan level).
Players receive experience points for each troop they donate. The number of experience points earned depends on the housing space of the troops donated; for example, donating 1 Archer earns 1 experience point whereas a Giant will earn 5 experience points and a Dragon 20 experience points. Players can normally donate a maximum of 5 troops per request (up to 8 can be donated in a higher level Clan with the “Donation Limit” perk).
Every housing unit of troops donated counts towards the “Friend in Need” achievement.
Clan Castles are the repository for bonus War Loot earned in Clan Wars. The higher level the Clan Castle, more loot can be stored (see summary table below). Loot stored in the Clan Castle must be collected before it can be spent. Stored War Loot can be stolen directly by enemies during battle. To store this bonus loot, miniature storages of all three types were added to the top of the Clan Castle.
If a rebuilt Clan Castle is destroyed in a raid, it will exactly resemble the original Clan Castle ruins. However, it does not need to be rebuilt again and will regenerate automatically like all other buildings.
If your request for troops is partially filled and then you use your Clan Castle in a raid (or dismiss some or all of the troops inside), your request in clan chat will still show the number of troops that your clanmates had already donated even though it is now empty. For example, if your Clan Castle had 10 of 20 spaces filled when you used it, your request in clan chat will still show 10/20 and not 0/20 until you request again.
When the Clan Castle is selected, the activation radius can be seen like the range of a turret. It is the only building (other than turrets and Hero Altars) that has demonstrates this behavior.
If the Clan Castle is destroyed while defending, any troops remaining inside will not be able to deploy until it regenerates completely (although they are perfectly safe and will remain there until the next battle). This can happen when only air troops are used to destroy it and some or all of the troops inside can only target ground troops (and thus will not deploy).
It’s ideal to place the Clan Castle near the center of the village so that the troops within will respond to attacks quickly from any direction. This will also make the clan castle hard to lure, allowing the reinforcements to maximize damage inflicted on attacking troops by attacking along side defensive structures.
Although the Clan Castle is a very useful building for defensive purposes, troops which target defenses (Giants, Hog Riders, Balloons and Golems) will not preferentially attack it (they will only do so once all defenses are destroyed, and only then if it is the closest building to them). In addition, even though the Clan Castle can now hold War Loot from Clan Wars, Goblins will neither preferentially attack it nor inflict double damage upon it, regardless of whether it currently holds loot or not.
Defensive units that survive an attack, regardless of their health level, will return to the Clan Castle at full health (if deployed offensively, they will need to be replaced regardless of whether they survive or not).
It is crucial to try to lure the troops out of the defending Clan Castle when attacking. Players can do this by deploying a single unit within the range of the enemy’s Clan Castle. This is to prevent a situation where players are forced to fight these troops within range of the enemy’s defenses. It’s also useful to know what type of defending troops are in the Clan Castle before deploying the whole army (e.g. you don’t want to deploy mass Barbarians when the enemy has Balloons defending his base). If you cannot reach the castle’s radius from the outside of the base, then use 1-2 Hog Rider(s), as they can get closer by jumping over walls.
Once the enemy troops are fully lured out (if your luring troop(s) die before all enemy units are deployed, you will need another lure) then take them out with a Lightning Spell or Poison Spell or lure them out further and dispatch them with whatever troops you have.
After luring the troops out, a player can choose to surrender the battle (if you decide these troops put you in a disadvantageous position), ignore them (not recommended), kill them with a Lightning Spell or Poison Spell or lure them farther away from the defensive buildings before battling them with your own troops. Note that once deployed, Clan Castletroops no longer have a trigger radius and will travel the entire length of the map to attack any enemy units. Use this to your advantage to draw them as far away from the defensive buildings as possible.
An easy way of handling strong troops (level 5 or 6) is to lure them far away from the base. Place one Giant at a far side, wait for the Troops to come close, and then deploy Archers in a circle around them; they should be taken down easily.
If a Clan Castle has no Clan shield, it can still have troops in it from previous clans.
Clash of Clans Clan Castle Upgrade Differences
When it first appears, it is ruined (it looks like the top has collapsed or the building has been damaged by an explosion).
When you initially rebuild it to level 1, it appears as a square stone structure with sloped sides. It is adorned with a single window, two grey metal doors and a wooden roof.
At level 2, a battlement platform is added to the wooden roof of the Clan Castle, resembling that of a level 8 Town Hall. A second window appears as well.
At level 3, four corners of the Clan Castle receive wooden supports, and shields are added to each corner of the battlemented platform.
At level 4, the wooden supports are replaced with stone supports. The wooden roof is opened, revealing a ladder leading down inside the castle itself. The exterior of the Clan Castle receives gold embellishment on the doors, between the windows and on the shields.
At level 5, the Clan Castle receives the same grey-black coloring as the level 9 Town Hall. The walls become vertical and there are stairs down from the roof. There are black shields on the edges of the Castle.
At level 6, the Clan Castle still has the same grey-black coloring the only differences are that the black shields are replaced with golden ones, and the corner battlements are lower.