The Amazon is an archer- and fighter-class hero from the base set.
Amazon Archer (Level 1)
The Archer has a Strength rating of 4. She has a Physical Attack of +1, and gains an additional +2 against Ranks 2 or 3.
Amazon Huntress (Level 2)
The Huntress gets an increase in Strength to 5. She has a Physical Attack of +2, with an additional bonus of +3 at Ranks 2 or 3.
Amazon Queen (Level 3)
The Queen gains another Strength increase up to 6. She has a Physical Attack of +2, with an additional bonus of +4 at Ranks 2 or 3.
Rulings and Errata
As currently worded, the Amazon does not provide a bonus against Rank 4 when used on the Wilderness side of the Thunderstone Advance board that comes with the Towers of Ruin.