The Princess is a Minion that promotes to a Queen.
While the base cost stays the same for tier 1-4, the penalty scales with upgrades, so princess have a morale penalty on death.
"Do not underestimate me." -- princess in game tip
Quick Stat: Princess Edit
|Tier 1||Tier 2||Tier 3||Tier 4|
Tier 2: Princess+ Edit
To Upgrade from Princess to Princess+, you need 4 Princess and 75 Dragon Coins.
Tier 3: Princess++ Edit
To Upgrade from Princess to Princess++, you need 4 Princess+ and 300 Dragon Coins.
Tier 4: Princess+++ Edit
To Upgrade from Princess to Princess+++, you need 4 Princess++ and 1500 Dragon Coins.
Strategy: Princess Edit
The most obvious strategy for the Princess is to keep it safely covered under the protection of ally pieces until the board has less pieces on it. When there is enough space, the Princess can move to the other side to promote to the very powerful Queen. To help achieving this, a variance of pieces can be used e.g. Harpy, Windmage, Wizard (for swapping places) and LifeStone (for reviving Princess if captured). Re-enchanting princess with Enchantress can also be a plausible strategy in late-game to get a promotion, although be warned-- the queen will not be enchanted!
Strength: Princess Edit
It begins the game enchanted, making it immune to (melee) attacks. This can be used to run the princess all the way to the other side ( With a +++). If you get it there you get a Queen+++, a normally very expensive Champion. This can easily swipe the king of the field. In a deck with strong attackers, a promotion can also save the game if you lose your king, as adding 28 morale allows stalling for quite some amount of time for a checkmate to the other player.
Weakness: Princess Edit
The Princess cannot attack, making it extremely fragile. The lost of morale is also quite severe at later levels, making it only fair trades for minions and highly susceptible to forks (at +++, it loses just as much morale as paladin++!)