As weeks of adventuring go by and your character gains the usual skill points and perks, you will notice a gradual increase in your power and ability.
Once in awhile, at the GM’s discretion, however, you will accomplish a task worthy of a major leap in power. Hence, the character Tier. In addition to the normal bonuses from increasing your Tier your GM may give you bonus skill points, and/or assign you a special Perk, spell, or ability of his/her choosing. Keep in mind also that not all characters will ascend tiers at the same time in some cases.
Tier 1: This is where you start. Tier one characters modify all stresses by 1, and both favored stresses by an additional one (choose your favored stresses carefully). Tier 1 characters have 1 aspect and their ability scores and skills max at 6.
Tier 2: Tier 2 characters can modify all saves by 2 now (same goes for their favored stresses). Tier 2 characters have 2 Aspects and their skills and ability scores now max at 8.
Tier 3: All save bases increase by 1 again to a total of +3, and again for favored stresses. Characters gain their 3rd and final character aspect, and all skills and ability scores can now max at 10.
So, the breakdown is as follows: Base stress and the two chosen class stresses are equal to the character’s current Tier, as are the character’s number of Aspects.
Keep in mind, some other features of your character are affected by Tier as well, for example: Second Wind heals a 3rd Tier character more than a 1st tier character. And casters of all types have a stronger Aura at Tier 3 than tier 1.