They appear similar to the Giant Skeleton due to their underbite (but are totally different in size), and have the same diagonal scar as normal Skeletons, but have a few exceptions like wooden spears which Spear Goblins bear, wooden shields, and Dark Prince helmets. They are also a bit bigger than normal Skeletons.
The Guards can be used effectively to counter a lone Sparky. With their shield, they can withstand a blow from the Sparky and destroy it before it shoots a second time.
The Prince is an excellent card for them to be used against due to them being able to tank a charge and 5 more hits. In fact, they can counter the vast majority of single-target troops.
The Guards can be countered with Area Damage troops or buildings. The Fire Spirits and Bomber are most effective, but the Wizard or the Bomb Tower are also good (but expensive) options.
Fire Spirits will take out Guards completely for a positive elixir trade.
Ice Spirit can be used to counter them, freezing them and allowing your Crown Tower to finish them off.
The Log can make short work of the Guards since it knocks off the Guards' shields making them weak enough for the arena tower to finish off.
The Guards are a good alternative to Barbarians if the player needs to keep their deck cheap as they cost two less Elixir. The trade-off is that the Guards have all-around lower statistics except for speed.
Level 3 or higher Guards' shields can survive a tournament standard Zap.
Guards are good for defending against the Graveyard since there are three of them attacking the Skeletons, and Guards cannot be defeated by a Fireball or Zap alone.
Guards are more effective at defending than attacking. It should be used to gain positive elixir trades and counter pushing. Sending them to push is usually not a good idea, due to them having relatively low attack speed and low speed. However, they can be effective with a Mini P.E.K.K.A.
When the Three Musketeers are coming to a Crown Tower without support, once the player's Crown Tower targets the Three Musketeers they can do a quick drop of Guards then Ice Spirit. The first guard will absorb the instant 3 burst shots from the Three Musketeers and then the Ice Spirit will freeze them for 1.5 seconds which is enough time for the 2 remaining guards and Crown Tower to finish off the Three Musketeers.
Guards are good against the Miner and Graveyard as they can easily disarm both of them while not being killable by Fireball or Zap.
Guards are actually able to attack from a very short range because of their spears, similar to the Prince. Due to this, they can poke at a distracted Valkyrie without taking any damage, setting you up for a counterpush.
They are not a good idea for offensive combos due to their low hitpoints and vulnerability to splash units. With that being said, they are great for counter-pushes when they survive from a defense. When using them for a push, they are typically best used to tank for the main push. Vice versa, if your Guards are out of rotation, you can use other cards to defend an incoming push, and cycle to your Guards. Once the units are done defending, the Guards can be dropped in front of any residual units, resulting in a strong counter-push, as the Guards can collectively tank 12 shots from the arena tower.
The Guards and the Dark Prince are the only 2 cards to have a shield along with their own health. Similarly, both have an Epic rarity, and both are unlocked at Arena 7.
No matter how much damage is inflicted onto the shield, the Guard behind it will remain intact, just like the Dark Prince. This means that not even a Sparky shot or Rocket can destroy a Guard while it still has its shield.
The Guards' spears allow them to have a slight attack range similar to the Prince against most melee units.
Because of the Guards' low elixir cost, they are a low-risk, high-reward card. They can eliminate ground troops like groups of Skeletons and can distract air troops like Minions, making them a good defensive option.