Many races have a Level Adjustment (commonly referred to as LA). This affects their maximum ECL (Effective Character Level). The more powerful the race, the higher the LA.
What does this mean?
On SCoD, the maximum level your character can reach is 30 - LA. So, the maximum level an Aasimar, with LA 1, can reach is 30 - 1 = 29.
ECL is the sum of your class levels (or Hit Dice) and your LA. So, an Aasimar Fighter 5 has an ECL of 5 + 1 = 6.
ECL is important when taking into consideration things like XP rewards and monster spawns, as they are based on ECL rather than total class levels (or Hit Dice).
When first getting started with high-LA races, XP adjustment and monster spawns based off LA are slowly added, rather than applying the full value from first level. 1 LA is added per level gained until the maximum LA is reached.
To explain this better, consider this table for a race with LA 5:
| Class Levels | True ECL | Adjusted ECL |
|---|---|---|
| 1 | 1 + 5 = 6 | 1 + 0 = 1 |
| 2 | 2 + 5 = 7 | 2 + 1 = 3 |
| 3 | 3 + 5 = 8 | 3 + 2 = 5 |
| 4 | 4 + 5 = 9 | 4 + 3 = 7 |
| 5 | 5 + 5 = 10 | 5 + 4 = 9 |
| 6 | 6 + 5 = 11 | 6 + 5 = 11 |
Once class reach 1 level higher than LA, ECL and the adjusted ECL reach parity. Prior to that the full penalty of being of a high-LA race is not in effect. This makes grinding at low levels easier, as XP from kills is not so badly impacted.