A machine abstract in nature, it is made of several exotic pieces and is used to tether arcanic resonances for the purposes of transmittance.
A junction machine is typically a crystalline container holding the ephermal 'machinery' which is primarily the interconnectedpieces floating within the apparatus.
http://homebrewery.naturalcrit.com/share/H17djGGwFX
Simple version:
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Ethereal Junction
- Wondrous item, very rare (requires attunement)
Of all the ingenius devices devised by the arcanically inclined, few mention junctions.
Acting as a circuit and amplifier, a junction is used to link one magical effect to another magical effect to increase the duration and/or strength of one using the other.
Physically, it is a 6 inch crystalline globe with what appears to be a crystal hour glass within. Inside that hourglass are several viscous fluids, encased and reactive to arcanic resonances.
Carrying an Ethereal Junction requires a devoted and careful hand during use as they are notoriously fragile, hence why there are few remaining in existence. If dropped, there is a 20% chance the device shatters.
If a junction shatters during use, DM's are urged to be creative and frightening. Remember to theme your disaster from the magics involved.
An Ethereal Junction requires attunement, which calibrates the device to the wearers arcanic resonance. If the wearer takes a fall or great impact, there is a chance the junction loses attunement with the user (DM's discretion).
To use a junction requires Linking.
Linking
4th-level abjuration
- Casting Time: 1 action
- Range: 60 feet
- Components: V, S, M
- Duration: Concentration
This spell activates a junction to boost an existing spells power using spell slots or another spell effect.
The spell must be cast at the level of the spell the caster wishes to affect.
Eg: A caster must cast Linking using a 5th level spell slot to affect a Wall of Fire, a 5th level spell. If the Wall of Fire was cast as a 9th level spell, Linking must be cast using a 9th level slot.
When a caster is powering a spell using a lower level spell, they must cast Linking at a level equal the difference between the two spells.
Eg: Casting Linking between a 3rd level spell and a 6th level spell, requires Linking to be cast using a 3rd level spell slot.
When a caster is powering a spell using a higher level spell, they must cast linking at the higher level to overtake the magic.
Once Linked, the spell affected lasts as long as the caster maintains concentration.
If concentration is broken, the caster must make a DC 12 Constitution save or suffer Stun for one minute.
The caster and the junction must be within 10 feet of each other and within 60 feet of any targeted effects. A caster takes control of a spell effect when they link to it using the junction.
When affecting a spell, the junction adds the difference in slots, if any, to the level of the spell effect being affected.