Psyche
Psyche includes an ability to work with magic/sorcery/ritual etc, with metal abilities including aspects of intelligence and learning as well as direct use of psyche to bend spoons, compel lesser minds to do the chicken dance in their underwear, telekensis and telepathy. It may be linked to the spiritual and less tangible supernatural including prophecy and forecasting. Abilities to use Powers like Pattern and Logrus as well as skill-based Powers such as Trump Artistry and Shapechanging are also primarily governed by Psyche.
Dworkin is probably the one with the highest psyche, with Fiona as the strongest mind of her generation.In the future, this stat could potentially be split, although where the divisions would lay are still up for debate.
Strength
Strength is the key stat with regard to physical challenges such as arm wrestling, grappling or unarmed brawling. Wrestling is a strength-based activity, as are Martial Arts with a focus on unarmed combat. It also determines pure acts of might, for example, how far a person of Amber or higher strength may pick up very heavy objects and throw them ie Flora’s Mercedes, the cyclopsean foundation stones of Garnath Castle, or Gerard’s food and ale consumption. It is also relevant for breaking jail bars, punching holes in walls of different materials and so on.Like Endurance, this is a physical development.
Gerard is known as the family strongman, and comparisons between him and the mythological character Hulk go on in Shadow endlessly.
Endurance
No matter what activity, Endurance is the measure of how long you can do that activity for, or hold out in the face of difficulties, and is a key factor in natural healing and regeneration. It can also modify the effects of environmental conditions. Who can endure a walk through extreme heat or cold longer? Who can swim in ice water and escape hypothermia?
It covers extended exercise, for example who can do push ups or run longer: for example Corwin and Random had a fencing match that lasted days and would have lasted longer except that one of them had a date. It also helps mitigate consequences of Shapechanging, and would be the deciding factor in how long two equally powerful spell casters can each throw spells at each other.
Corwin has the highest known Endurance.
Combat
This is purely armed combat, with weapons of any sort, from spear to rocket launcher, from sling to two-handed sword, from cudgel to rolling pin or cast iron frying pan. Martial Arts that are primarily weapons-based would also fall into this area. For plot purposes, if someone is highly skilled in the sword, even if their stats indicate that they should be equally strong with any other weapon, they may well be less effective at other forms of unrelated weapons, ie bow, rifle and phallanx spear.
One may assume that Benedict has strong working familiarity with all weapons while Brand has greater focus on a crossbow and Eric on his sabre.
Command
This is any leadership/stratetgy/tactical based skill involving others. This can be operating a small business to a corporation; or commanding armies navies and small combat units. Command includes logistics, operations, deployment, grand strategy, tactical maneuvers etc.For plot purposes, it is likely that characters may be stronger in some areas than others. For example, Armand and Ian are trained extensively in small unit operations which would be a plot related strength. Matthew is an armchair general who like Emperor Claudius, is skilled and experienced at Grand Strategy but would be much less effective at small unit operations.
One may assume Benedict is well skilled in all aspects of military operations.