The Minion Horde is a high risk, high reward card. It is a powerful defensive card and can easily be turned into a threatening counter-push. However, splash damage like the Wizard or Arrows will easily destroy the minions.
Despite their massive DPS, a Minion Horde can't always destroy a unit before it reaches your tower. For example, the Giant Skeleton and Hog Rider will both reach the tower either because of their hitpoints or their move-speed. Keep this in mind when facing similar threats and respond accordingly by placing a ground unit like Skeletons or a building.
Miner pairs very well with any surviving defensive units. As long as one Minion is still alive after a defence, it is always worth tanking for it with a Miner. It can also be played as a fast and lethal push when at an elixir advantage or you know that your opponent's counter is not in hand.
On a similar idea, it may be worth casting a Freeze Spell to allow the Minions to deal severe damage to the crown tower. This is especially punishing when you catch your opponent off-guard, for example, when they play Zap. One thing to remember is that it's the surprise factor that makes this effective so follow-up attempts may not be as successful.
The Minion Horde is extremely vulnerable to splash damage — most area damage troops and spells can eliminate it efficiently for a positive or neutral elixir trade.
All area-damage spell will be able to eliminate a Minion Horde when played correctly. Zap is the cheapest counter but it relies on your Crown Tower to finish them off. Its large area, fast travel time and cheap cost makes Arrows the most reliable counter by far. Fireball and Poison will kill a Minion Horde but Fireball has a smaller radius and Poison deals damage over time. The worst counter is Rocket. Although an achievable feat, its slow move-speed, tiny area-of-effect and high elixir cost makes Rocket an incredibly unreliable counter.
Troops are reliable counters and are an active presence in the arena. You can form a counter push with troops and they are usually better value than spells. Wizard is an exceptional splash unit. He has considerable burst damage allowing him to one-shot Minions and deals splash damage so two shots is usually enough to destroy an entire Minion Horde.The Executioner is an excellent counter to swarms in general due to his area denial attack. His axe can kill a Minion in 2 passes and will only require 1 throw to kill an entire Minion Horde. Due to the large area-of-effect the Executioner can also damage cards in front or behind a Minion Horde.The Witch is a great counter. Despite her tiny damage, her DPS is sufficient to kill a Minion in 3 shots within a very short period of time. Her spawned skeletons will distract the Minions to give her more than enough time to destroy a Minion Horde.
Minion Horde was added with Clash Royale's soft launch on 4/1/16.
On 3/5/16, the May 2016 Update fixed the "range bug" and decreased the Minion Horde's range to 2 (from 2.5) but their effective range is unchanged.
The description is a reference to the popular saying "two's company, three's a crowd".
The Minions in the card picture of Minion Horde are paler in skin color compared to the regular Minions, most likely due to the lighting of the area they are in. They also appear to be wearing pale reddish-purple fingerless gloves, as opposed to the indigo gloves worn by the regular Minions. However, the Minions of Minion Horde are visually identical to the regular Minions in battle.
The Minions on the card appear to have purple eyes despite the fact that their eyes are red in battle.
The Minions appear to have an underbite, similar to the Lava Hound.
The Minion Horde is one of the highest damage per second cards in the game. A lone Level 13 Minion does 123 damage per second, but you have to multiply that by 6 for the Minion Horde for a total of 738 damage per second overall. This figure is surpassed only by 2 other troop cards, the Skeleton Army (1,372 damage per second total at max level, but more vulnerable and cheaper) and the Inferno Dragon (1277 damage per second max level at the max tier).