CLASSES

Each character can pick a class that grants special bonuses as they level. You would be advised to play into their strengths but also ensure you find ways to compensate for their weaknesses. You can simply add skill points to weak areas or add to luck, find certain items, or try to avoid certain situations..

Assassin
Bastion
Cleric
Doomguard

Tricky Examples

You might build a Assasin and pump a lot of skill points in Dex and Luck.
Sure they are unlikely to ever be hit by melee attacks but one:
Hit, trap, spell or a virus might take them out instantly if their luck runs out!

You could build a glass cannon Cleric, they would be great at solving puzzles, obliterating, and crowd controlling their enemies.. but a single misstep, blow, or an enemy that's immune to let's say.. frost.. well.. game over.

Solid examples

A Doomguard naturally has strength and constitution as they level but will suffer penalties toward intelligence checks. Since they are already tanky and strong you might as well avoid dex but put points into luck and wisdom.
Wisdom would allow him to reflect on past experiences where his intelligence might not.. and luck can turn a roll of 2 into a natural 20!

Bastions are both a sword and shield, they will rely on self-sustain and preservation and will most likely outlast their opponent's barrage of attacks. Adding points in the constitution will ensure you will sustain and block successfully, and find your opponent's weak spot to strike. Spread other skill points out to become well-rounded, skilled in many but an expert of none.