The matchmaking algorithm is the unsung hero that determines exactly who you will face every time you press the 'Battle' button.

While this conspiracy theory is widespread, the reality is much more mundane and focused entirely on mathematical fairness.
The Elo System Adapted
The algorithm's primary goal is to match you against someone with the exact same—or very similar—trophy count.

When you go on a massive winning streak, your trophy count inflates, and the algorithm begins matching you against significantly better players.
If you are hovering around 50%, you are in the correct arena for your skill level.Queue times increase at the top of the ladder.You will eventually stabilize. The Free-to-Play Dilemma
The standard Elo system works perfectly for chess because all pieces are equal, but tower rush games feature upgradeable cards.

However, if no such player is available, the algorithm will prioritize queue speed over level fairness, resulting in those frustrating, mismatched games.
Player PerceptionHow it Actually WorksForced Loss StreaksThe algorithm does not force losses; you are simply playing tilted against harder opponents because your MMR is inflatedThe Deck Counter CodeDevelopers have confirmed repeatedly that the algorithm does not read the contents of your deck when finding an opponent True Fairness
Because the ladder algorithm must balance queue times against fairness, it will never be perfectly balanced.

The algorithm is blind; it only respects victory.