Summon one or more Heroes - pay with Ale. The Heroes summoned in the tavern tend to be less powerful than those from the Temple. You can summon up to six at a time, if you have enough Ale.
The Temple is where you can summon the most rare and powerful Heroes, for Gems or Summon Tickets. All Temple Summons give 3* or better Heroes.
Every Hero has a rarity - that is, how likely it is that you'll get that Hero when you summon. Note - rarity is different from the Hero's Power - which is denoted by the number of stars they have.
The levels of rarity are: