There are a few basic rules when considering castle troops.

Immunity to Poison Spells

Assume that the enemy will use a poison spell to deal with castle troops. Your war castle defense troops should be built around a fundamental core that is relatively immune to poison spells. These troops are in order:

• Lava Hound (7600 HP)
• Golem (7200 HP)
• PEKKA (6300 HP)
• Electrodragon (4200 HP)
• Dragon (3600 HP)
• Baby Dragon (1700 HP)

The poison spell does a maximum of 220 HP per second and decreases troop movement and damage speed by about 50%. For example, an Electrodragon takes 3.5 seconds between attacks. Under a poison spell, it will take (3.5 x 150%) = 5.25 seconds to attack. Combined with the DPS of the poison spell, the DPS of a high-level Archer Queen can take out the Electrodragon before it can attack.

The fastest attacking tanking troops are the Dragon (1.25 seconds) and Baby Dragon (1 second). Both of these troops have advantages. All Dragon-type troops have splash damage and the Baby Dragon has rage mode. The Electrodragon has longer splash radius plus relatively insignificant death damage (60HP per exposed troop).

• Baby Dragon (1 second)
• Dragon (1.25 seconds)
• PEKKA (1.8 seconds)
• Electrodragon (3.5 seconds)

Therefore, against enemies with high-level Archer Queens, the Dragon and Baby Dragon are preferred.

Against enemies with moderate or low-level Archer Queens, the Electrodragon is a candidate.

Ground troops (i.e. PEKKA) are generally ineffective against air attacks, so I don’t recommend a ground troop as the core defense troop.

High DPS

The best attacking troops will have a combination of tanking hitpoints (HP) and damage per second (DPS). High hitpoints allow the troop to remain on the battlefield longer, absorb more damage, and allow surrounding defense weapons to inflict damage. Golems and Lava Hounds have high hit points but low DPS. If the enemy lures the Lava Hound away from defensive weapons, it is basically useless. The castle troop needs to have high DPS.

The highest DPS troops by housing space is illustrated below. I used the Geometric Mean of each troop’s DPS and HP to calculate a relative rank:

For example, the Balloon occupies 5 housing space and offers 236 DPS. This is 47 DPS per housing space. It has 840 hitpoints, giving it 168 HP per housing space. Calculating the geometric square is sqrt(47 x 168) = 89.

Below is the relative rank of each of the key troops:

The Balloon is the undisputed champion of the most DPS and HP per housing space. I had to add in the DPS and HP of spawned troops for the Witch and Lava Hound. The Lava Hound ranking is deceptive because all of the DPS comes from the Lava Pups, which are easily killed with a poison spell. Therefore, a Lava Hound is not recommended because the DPS (pups) are decoupled from the HP (Hound). The PEKKA is only effective with ground troops and doesn’t protect against air attacks.

Movement speed is a major issue that should be included in the analysis. Slow-moving troops are easy targets, especially under a poison spell. Below is a geometric square ranking of troops including movement speed:

Again, the Lava Hound is deceptive, because the high Pup movement speed (32) skews the results. The Valkyrie fares extremely well.

Observations

• The Dragon is resistant to the poison spell and deals splash damage. It consistently beats the Electrodragon (per housing space) for DPS, HP, attack speed, and movement speed.
• The Baby Dragon in rage mode stands out. However, no other air troops can be used because the Baby Dragon must be alone to achieve rage. The Baby Dragon’s relatively low hitpoints make it an easy target for high-level Archer Queens.

Possible Troop Combinations

Here are some recommended troop combinations and supporting calculations using the geometric mean equation:

30 Housing Space

• Baby Dragon, 2 Valkyrie, 1 Wizard (score: 65)
• Baby Dragon, 1 Witch, 1 Valkyrie (score: 72)
• Dragon, 2 Balloon (score: 68)
• Electrodragon (score: 37)

35 Housing Space

• Dragon, 3 Balloon (score: 71)
• Dragon, Baby Dragon, Balloon (score: 58)
• Baby Dragon, 2 Witches (score: 74)
• Baby Dragon, 3 Valkyrie (score: 62)
• Electrodragon, 1 Balloon (score: 47)

Conclusions

The basic rules of this analysis can be summarized by:

• Each defensive combination needs to be built around a high HP core troop resistant to poison spells.
• The core troop should also have high DPS.
• All Dragon-type troops have splash damage to affect attacking troop clusters.
• Attack speed is important, especially with the speed penalty of a poison spell.
• Movement speed is important, especially with the penalty of a poison spell.
• Versatility of attacking both ground and air is important.

The best core troops, in order, are:

• Raged Baby Dragon
• Dragon
• Baby Dragon (combined with other air troops)

The best supporting troops, in order, are:

• Witch (ground and air, spawns skeletons)
• Valkyrie (ground only)
• Balloon (ground only)

What about the Electrodragon?

The Electrodragon appears to be a feasible defense troop for enemies with moderately low-level Archer Queens. Higher level Archer Queens can kill the Electrodragon with relative ease, especially combined with a poison spell. Electrodragons would also be effective against attacking LavaLoon armies if not lured out of the clan castle prior to launching the attack. Skilled LavaLoon attackers should always be expected to lure the Electrodragon using a killsquad before releasing the Balloon army.

What about the PEKKA?

The PEKKA is a formidable tanking defense, but has slow attack speed (1.8 seconds), slow movement speed (16), no splash damage, and inability to attack air troops. The PEKKA would be useful against TH8 or TH9 attacking ground armies (i.e. GoWiPe), but otherwise generally ineffective.