Mechamagic is what I am calling the blend of mechanical power and eldritch energy that made up much of the incredible array of items and machines that ran, and ran through, the Machine City centuries ago. The Clanking Ruin, the husk of the the Machine City, is a ruin, filled with danger, adventure, and amazing items and machines that are found nowhere else.

Just as with regular magic in Glorantha, Runes form the basis upon which Mechamagic was built. Mechamagical Runes underlie power, augment, and alter, most mechamagical things in and around the Clanking Ruin. Mechamagical constructs like Forge-Knights (Earth and Movement) or Manchines (Death and Undead) embody one or more Mechamagical Runes. And often as not, the runes that are combined are antithetical or nearly so. This is just one of the things (although a big one) that caused the ancient champions of the established gods to pound the Machine City to rubble and ash in the Gloranthan version of the Trojan War.

Mechamechanical Runes are modifications of normal runic principles, Like Life or Death or Air or Earth, combined with the Mechanism rune that was developed by the sorcerers of the Machine City. Thus there are Plasmechanical Runes, and Electromechanical Runes, and more, each combining aspects of other runes (like Fire/SKy or Air/ Storm in those examples) with the Mechanism Rune.

When these runes are given physical form, generally by being scribed upon, and magically bound to a physical item, this creates a Mechamagical Rune Matrix which can be used with relative safety.

Mechamagical Rune Matrices can be inserted into a mechamagical item or construct with appropriate skill checks, granting that item access to the runic power it contains. Some items are crafted with an access port to accept matrices. in these cases matrices can be inserted or removed easily by anyone, usually just by taking an action or two to do so.

So a matrix could be added to a Forge-Knight by making a number of skill checks on Skills like Mechanisms or Mechamagic. Thereafter, the forge-knight would be able to use the power of that rune as it does any other ability. Or a Matrix could be inserted into a bracer built for this purpose, granting the rune's power to the wearer.

Here are a few ways that Mechamagical Rune Matrices can be used:

Bracer: A mechanical arm harness that allows the installation of a single Mechamagical Rune. The Bracer must be attuned to the weare for access to any Rune Matrices, but individual rune matrices need not be, themselves attuned. Matrices can be easily removed, and a new one inserted, in which case the ability of the old matrix is no longer available, but the ability of the new one can be accessed.

Motor: A complex harness that accepts one or more Mechamagical Rune Matrices, and is then installed into a construct as its motive force. Usually there is also an accessible Charge Node of some sort  that allows the Matrices to draw power for external energy sources. This is how Forge-Knights and Manchine are powered. Forge-Knights have a motor incorporating the Fire/Sky/Mechanism or Storm/Air/Mechanism runes, whereas Manchines have a motor incorporating the Undeath/Mechanism Rune. Other such sources are possible, like the Water/Fire/Mechanism rune, or the Earth/Movement/Mechanism rune.

Prosthetic Organ: An organ that provides energy, or the implanted Rune's power, to the person bearing it when they attune the rune, not unlike the motor implanted in a mechamagical construct.. This might be to replace a damaged organ, or to improve function of the existing one. Manchine have artificial kidneys (incorporating the Death/mechanism rune) that recycle some of their biotic fluids. Scholars believe that this organ is crucial to the creation and maintenance of Manchine status. An Integral Energy Matrix (using the Magic/Mechanism rune) can also be installed as a source of Magic Points.

Prosthetic Limb: A limb that bears a Rune Matrix grants the use of the Rune to the one who attunes the limb. Forge-Knights, as well as mortal organic creatures can benefit from an artificial limb with a Rune Matrix.

Prosthetic Mask: An augmentation for the head of an individual. Sometimes such prosthetics contain Runes that aid in perception, or grant new forms of perception. But most other Matrices are portable to a Mask. Forge-Knights and other constructs can make use of a Prosthetic Mask as easily as an organic wearer.

Here are some sample runes. There are many more. Ranks of Rune Effect are limited by the INT of the Infusor/caster divided by 3, Round Down.

Plasmechanica Rune

Progressive

Range: Touch

Duration: 5 Minutes

Each rank of this spell costs 3 POW, and infuses a Mechanomagical Construct or Device with Plasma. The caster can, over the course of the 5 minutes:

• Make a number of melee attack adding 1d6 Bonus Plasma damage with each successful attack.
• Cast a single plasma bolt (1d6 per rank) at one target up to the owner’s POWx5 in Yards away, ending the duration immediately.

The Starting Percentage for Plasma-Casting is Based on INT+DEX.

Electromechanica Rune

Progressive

Range: Touch

Duration: 5 Minutes

Each rank of this spell costs 3 POW, and infuses a Mechanomagical Construct or Device with Electricity. The caster can, over the course of the 5 minutes:

• Take a number of additional Move Actions equal to ranks in the power.  
• Make a number of melee attacks adding 1d10 Bonus Electricity damage to each successful attack.
• Cast a single blast of Electrical damage (1d10+Ranks damage) up to the owner’s POW in Yards, designating up to as many targets as there are ranks in the blast, ending the duration immediately.

The Starting Percentage for Electro-Casting is Based on POW+DEX.

Disrupt Mechanica: Spell or Mechanica Rune

Progressive, Magnitude 2

Range: POW x3 in Yards

Duration: Instant

This spell costs 1 POW per rank to cast, and damages only items or objects. Rank 1 does 1d4 to a random location, ignoring AP, and 1d4 to the objects POW, if it possesses any (as in the case of a Mechamagical Construct or Device). Each Rank that is added to the spell, does 1d4 to another location OR 1d4 to the object’s POW.

False Life Rune

Progressive

Range: Touch

Duration: 5 Minutes

Each rank of this spell costs 1 POW and can restore 1 lost POW, or 1d3 lost HP to one or more locations of a Mechamagical construct. The POW can only replace Temporary POW, and the Hit Points last only for the Duration of the Spell. The HP do not alter the Total HP loss, only the HP damage to locations.

Stone-Sight Rune

Progressive

Range: Self

Duration: 1 Minute

Each rank of this spell costs 2 POW and allows the rune-bearer to see through 1 foot of stone as if it were all but invisible. The structure is still noticeable, and sight of things that would normally out of sight is slightly hazy (-20% to Spot checks).

Many More Machamagical Rune exist - More another time.