on my system (classless) characters are build with these rules:
OBSS has no classes. At each level player can decide to improve the score of Weapon Proficiency or Magic Proficiency. With the first you hit better, with the second you cast spells. It is the Feats that build the character's abilities, the class.
Magical Proficiency:
The higher the MP score, the more spells you can cast and the harder it is to resist the spell.
Having a high MP score leads to knowing more magic lists even if in a very superficial way.
Weapon Proficiency:
Every time you give Weapon Proficiency a point, you can assign a point to a list of weapons, i.e. a homogeneous set of weapons. You can learn more lists of weapons and therefore know many different types of weapons or specialize in certain "families" (swords, axes, clubs ..) acquiring with experience more and more spectacular skills with use.
Skills:
The skills (knowledge, athletics, cheating...) are not chosen at the first level, but a profession is chosen and this grants 4 skills, then the player chooses a fifth from the background.
The higher the value of the skill, the faster it is usually to carry out the action of interest.
As you level up your skill scores can be increased or new skills taken.
Feat:
Since the character has no class, choose the ability (Feat) to build it. There are over 120 Skills to choose from, many can be taken multiple times to "unlock" further extraordinary abilities. Skills are taken at all levels except 5, 10, 15, 20 level.
Skills increase saving throws. Each time you take a skill you increase your saving throw scores, this is the only way to increase your saving throws.
Ability increases (ASI) are taken through skills.
Combat:
....
- multiple attacks take the value of the roll to hit and for each roll after the first then subtract 5. So if you have +12 on the roll to hit make one attack at +12, one at +7 and one at +2, if it is negative you can't do it. In practice, the number of attacks depends on your skill rather than just on the level.....
and a lot more.. example of text taken from
TUS/OBSS-in-short.txt at master · buzzqw/TUS
BHH