Oroborus was developed from the general rules of Ysgarth and To Challenge Tomorrow, with design goals of being a generic, universal system and being an easy-to-learn and use system. Note that Oroborus and Ysgarth characters are both playable in either rule system. The rules received substantial play-test and went through several major and numerous minor revisions. The final Version 2.8 was completed for publication (even receiving an ISBN) but has never been published. The rules included three major genre supplements which progressed through full development and cover art but likewise have never been published. These materials were freely and generally available online in HTML format until shortly before the planned publication date at which time they were removed.
Characters have four Mental Characteristics (Charm, Reason, Will, Creativity) and four Physical Characteristics (Constitution, Strength, Dexterity, Agility). Characteristics (Attributes) have a numeric score ranging from 1-24, with 11-14 being average. Characters have several Secondary Characteristics, most of which are derived. Characters also generate a list of Skills with associated Ratings. The Skills are detailed in two separate HTML pages; they are assigned to genre groups, and sometimes assigned to specific nationalities or time periods as well. Skills are usually divided into "secondary" applications and, particularly in combat, even further divided into "tertiary" applications. Characters may have specialized ability in a secondary or tertiary application.
Various "supplemental" abilities (psionic, magic, super powers) are grouped under Paranormal Skills. These Paranormal Skills have additional complications compared to standard Skills. The heavy support for these types of abilities indicates the system's investment in the fantasy genres. Combat is generally simple but does offer added complexity through numerous options and maneuvers. Actions in combat are limited by Action Points--each action has a cost and when the character runs out of Action Points their activity for the round is done.