Item construction follows the rules in the book, for the most part, with the exceptions noted below. If you want an item to do something that doesn't seem to be on here, talk to me about it.
Defining Why An Item Works
Why does your horse run at 75 mph? Why does your sword slice through normal steel as though it's warm butter? Why and how items have the exceptional powers they do is important, as it determines which Shadows the item will and will not function in.
These are examples of possible principles on which exceptional items could function. You may be able to think of others.
Magical: The item has been enchanted with the exceptional abilities. This is adaptable enough that the item will work in any generally "magical" Shadow, although its effectiveness may vary from Shadow to Shadow.
Technological: The item's abilities come from its being a particularly advanced piece of technology. A Deadly Damage sword might use monofilament or force weaponry technology. Again, this is adaptable enough that it will work in Shadows that are primarily technological in nature, such as Shadow Earth.
You also have the option of buying items containing Reality, which will generally have been forged by arcane means involving the Pattern (Greyswandir) or Logrus (Frakir, Mandor's Steel Balls). These items have the advantage of working anywhere, and the disadvantage of costing more points.
An item operating on a Reality principle costs twice the base point cost, and you must have an appropriate background or power depending on what you want it to be based on. Possible principles include Pattern, Logrus, Broken Pattern and Trump. In addition to the advantages of the item being free of less primal technological or magical restrictions, it will have certain abilities depending on the principle powering it: a weapon with Pattern in it, for example, will do extra damage to Chaos dwellers (like Greyswandir does) by igniting their blood.
You may take a single Reality item of up to 10 points at the beginning of the game without the doubled cost. This your character's "signature" item, his or her Greyswandir/Frakir/Steel Balls/White Scale Armour.
Comparable to character attributes, these define the item physically and (possibly) mentally.
Vitality: as the DRPG book.
Movement: as the DRPG book.
Stamina: as the DRPG book, except that "Tireless" only provides the kind of stamina that someone with low-Ranked Endurance would have.
Aggression: as the DRPG book.
Resistance to Damage: as the DRPG book.
Weapon Damage: as the DRPG book.
Intelligence and Communications Skills: as the DRPG book.
Psychic Quality: as the DRPG book.
Psychic Defense: as the DRPG book, although Psychic Barrier will be considerably less potent than a literal reading indicates-- more like armour than an impenetrable barrier, meaning someone with a strong enough Psyche or another means of boosting their attack will simply be able to punch through it.
Item Movement Through Shadow: Items or creatures that have the ability to move through Shadow must be designated as operating on the principle of Order, Chaos or Trump. Because of this, they must be Reality-based items.
Item Control of Shadow: As above.
Item Healing: There is no Regeneration Power, due to its being twink-a-riffic. Items with 4 points in Healing simply receive a comparatively greater ability to heal their wounds or repair themselves, in rather the same manner as someone with low-Ranked Endurance.
Item Shape Shifting: As with the 4-point version, any forms assumed by the 1-point and 2-point versions of this power must be of comparable size and mass: no rings that turn into swords and cars. Alternately, you may pay 2 points for an item that has another form of greater mass and size (a ring that turns into a short sword is about the upper range of this), or 4 points for an item that has up to a dozen different alternate forms of this type. 4 points will buy you a single alternate form of radically different mass and size (a ring that turns into a car, a cat that turns into an elephant).
Item Trump Images: "Powered by Trump" is covered by "Defining Why An Item Works", and can have either a reduced or increased point cost depending on the base cost of the item. The 4-point version will give you an item (a cloak, a shield, a painting like the Tree of Life that Luke gave to Victor Melman) with up to a dozen trump images on it.
Power Words in Artifacts and Creatures: as the DRPG book, except for the clarification that if the item is part of your personal reality you must have Power Words, and the item can only have Power Words that you know.
Spell Storage: as the DRPG book, except that the 4-point version allows the item to rack and use only a single spell.
Only the followng Qualities may be transferred: Vitality, Movement, Stamina, Aggression, Psychic Quality, Psychic Defense.
Only the following Powers may be transferred: Movement Through Shadow, Control of Shadow, Healing, Power Words.
Transferal must be a willed act on the part of the item's wielder. You can't give Benedict Chaos Warfare by tricking him into putting on a Conferred Combat Training ring, or otherwise.
As the DRPG book. The Quantity Multiplier applies along with the multiplier for making items operate on a Reality principle, so Named and Numbered Reality-based items will have a 4x modifier to their base cost.