Pick a species. Most non-human species have a +1 to one stat, and a -1 to another.
Pick a class.
Calculate stat modifiers:
Stat
Mod
2,3
-4
4,5
-3
6,7
-2
8,9
-1
10,11
0
12,13
1
14,15
2
16,17
3
18,19
4
Leveling up
at Level 2, give each stat a percentage of progress towards the next integer by rolling percentiles.
per each further level, the progress will go up by 1d20 percent on one of your class's prime attributes, 1d6 on the weakest of the other stats, and 1d10 on the rest.
