The Osiris Rollenspiel (Osiris RPG) is a German small-press rules system. It uses a percentile system for all checks (roll under a skill or attribute with d100).
Osiris characters have five attribute groups with three attributes each. Besides the usual attributes like strength or intelligence, there is a "psyche" group with the three attributes Es, Ich and Über-Ich (id, ego, super-ego), based on the ideas of psychologist Sigmund Freud. They influence the decision-making of a character and show if he is ruled more by his instincts or more by his mind. During character creation, the player is given a number of points to distribute between the 15 attributes.
Each character also gets a set of randomly determined strengths and weaknesses. Strengths and weaknesses come in pairs like optimstic/pessimistic. A value from 1 to 6 determines to what side the character tends.
Skill base values are calculated using a primary and a secondary attribute. Skills can be improved by spending character points. Beginning at a certain skill level, a character can fail to improve, losing the character points he invested.
Magic is based on skills and a learned set of spells of different difficulty levels.
In combat, every character has a number of action points based on his attributes. Attacks and defensive actions are skill checks. Attacks are modified by the armor rating. Damage is calculated by multiplying a weapon's base damage with the result of the attack roll. The Armor rating reduces this damage value. Damage is then subtracted from a pool of vitality points.