If you choose to reuse, copy, reproduce, reiterate, ninja, or snipe the content; do it all you like as long as you mention the origin in some way, shape, shift, or form.
A medium is someone with a connection to the spirit world. The idea is that this class can summon spirits, reanimate slain demons/monsters (by channelling spirits through corpses) and buff themselves and other party members by casting seances (similar to a slam dance), etc, etc.
Parabola - Channels energy through a focus point where it is intensified (similar to disintegrate beam in appearance) - Runes can affect it in ways such as Paranoia/Damages other enemies like friendly fire, Sickness/Poison, Self Loathing/Slow like cold, Spontaneous combustion/Fire (will spontaneously combust enemies if it inflicts the final blow).
Shame (Humiliate) - Casts a debuff and also a buff depending on the rune. Things like enemies take more damage, and party members increased crit chance. The idea is to weaken enemies and strengthen allies by inducing memories of shame.
Etherealise - This could be a form like Archon form for Wizards where the Medium can channel through a crystal or some sort of fractal manifestation; which could be placed like turrets, or just cast directly as a beam or resonating wavelength/seismic disruption to living flesh. Could also cast things like Deregulate - which alters frequencies of enemies (inflicts damage over time, slows, or causes increased damage). Other matter manipulating skills such as Splitting Atoms which could be like a knock-back AOE.
Séance - Like Slam Dance for Witch Doctors, but causes phantasms of each party member in the circle to manifest and increase damage or resistances (by 20% for example), or even be an illusion of the entire party which attracts all enemies so every member can escape. Phantasms could be ethereal clones that transparently appear just behind each player and behaves as a mirror double. Could also de-buff enemies by creating phantasms of the enemies: leaches that drain their health/damage ability/stunning and slowing.
Project - Like a spirit walk although enemies follow the spirit and you can either choose to materialise where you led the spirit double, or the starting point as if you used the spirit to lure enemies away from your body. Could also combust the spirit as an AOE where inflicted damage could be things like: Misery (slowdown increased damage taken), Delusion (confusion), Possess (Reanimate enemy as an ally on death), Disrupt (interfere with resonating wavelengths causing explosion to which other enemies in radius have chance to be disrupted also).
Summon - Pretty much self explanatory. Summon spirits to reanimate corpses, to buff yourself or party members, or to cause grief to enemies as a de-buff.
Smoke and mirror - Primary attacks such as light flashes, or darts of smoke which do not cost resource.
Name of Resource
Echoes - An orb of echoes or summoned impressions, or Impressionable Ether (easily malleable ether)
Ubiquity - The essence of interconnectivity between everything.
Etherium - As above
Off Hand Ideas
Crystals/Elements in pure forms
Whip/Cat of Nine
Sling (can whip, flick projectile, swipe, leave ground effect, etc)
Gazing Mesmerism (Helm)
Ethereal Meddling (Gloves granting resource bonuses or summoning proccs)
Never Presents (Boots granting Projection bonuses)
Ominous Arrhythmia (Amulet)
Dead Poet's Uniform