Merge & Blade

To earn this achievement you must have upgraded the academy to level 4 and match 3 or more of the lower level troops until you create the priest.

These are the Academy upgrade costs and unlocks:

Academy level 2 – 0 gold unlocks rogue
Academy level 3 – 500 gold unlocks archer
Academy level 4 – 1,200 gold unlocks priest
Total gold = 1,700

This is the order of troop upgrades:

Farmer – Blacksmith –Footman – Rogue – Archer - Priest