Ability Scores and Hp
Athas is a dangerous world and only the strong survive here. As a result a tougher breed of adventurer is required.
The starting stats for an Athasian Campaign are 18,16, 14, 13, 12, 10. It is possible through racial modifiers to raise these above 18.
Characters gain maximum hit points per Hit Die at first level and their Consitition score instead of Constitution modifier as a bonus at first level. At later levels hit points are gained normally.