Ephemeral allies are available in this game via the Ghost Ally merit, and the Familiar merit. The former is available to all templates, while the latter may only be taken by certain Thaumaturge traditions.
Ghost Ally is modified slightly from the book version to fit into the GMC Ephemeral mechanics. Below are some of the changes, follow by a write up form.
First: Decide on how many dots to spend on your ghost, then follow the guidelines on Second Sight, p. 65.
Rank: This is an Ephemerals overall power level. This is calculated by the number of attribute dots. If the ghost has 8 or below, they are Rank 1. 9 or above, rank 2. Rank is generally used any time a roll calls for Supernatural Advantage. (Eg, resisting a power being used on the ephemeral.)
Essence: At rank 1, an ephemeral has 10 essence. At rank 2, 15 essence. Ghost allies do not bleed essence, unless they leave the presence of the PC. For full rules on essence, see GMC p. 219.
Attributes: Per the write-up.
Influence: One dot per rank. For a Ghost Ally, it always Influence: Anchor. See GMC p. 222
Manifestation: All Ephemerals start with the Twilight Form manifestation. They receive 1 additional manifestation per rank. These are found on GMC p. 224. Ghosts are automatically anchored to the character, and additional anchors may be bought per the write up.
Bans: These are compulsions that an ephemeral must do or not do. Your ghost needs one ban. See GMC p. 221 for full rules.
Banes: These are materials that damage an ephemeral's corpus. Banes are solid and hurt an ephemeral (and deal aggravated damage) even if the ephemeral is in Twilight. Your ghost needs one bane. See GMC p. 221 for full rules.
Numen: Ghosts get one, though can buy more with additional points. See GMC p. 228
Ghost Ally Note
Please make your Ghost Ally note look like this:
This merit is available to Thaumaturges, and mostly follows the book, with some modifications to incorporate GMC rules.
First: Is it Twilight or Embodied? Apostles and Shamans get Twilight, Hedgewitches get Embodied. See Second Sight, p. 109.
Rank: Familiars are Rank 2. This is an Ephemerals overall power level. Rank is generally used any time a roll calls for Supernatural Advantage. (Eg, resisting a power being used on the ephemeral.)
Essence: 10 essence. For full rules on essence, see GMC p. 219.
Attributes: Familiars start with 1/1/1 for their Power/Finesse/Resistance. Distribute an additional 3/3/2 between attributes as you see fit. Note: Embodied familiars will ALSO use Power/Finesse/Resistance.
Influence: 2 dots in one influence type. See GMC p. 222
Manifestation: Twilight familiars start with the Twilight Form Manifestation and choose 2 more (Consider: Reaching, Gauntlet Breach, Image, Materialize, or Unfetter). Embodied familiars start Twilight Form Manifestation and the "Embodied" manifestation (they cannot un-manifest, unless their corpus is destroyed), and choose 1 additional (Consider: Reaching, Gauntlet Breach, or Unfetter). Consider taking: These are found on GMC p. 224. Familiars are considered to be tethered to the character.
Bans: These are compulsions that an ephemeral must do or not do. Your familiar needs one ban. See GMC p. 221 for full rules.
Banes: These are materials that damage an ephemeral's corpus. Banes are solid and hurt an ephemeral (and deal aggravated damage) even if the ephemeral is in Twilight. Your familiar needs one bane. See GMC p. 221 for full rules.
Numen: Embodied familiars get Innocuous (-2 to be noticed), plus one. Twilight familiars get one. See GMC p. 228
Please make your Familiar note look like this:
As above, ephemerals have a number of manifestations equal to Rank + 1. All Ephemerals have Twilight Form chosen for them. Embodied Familiars have the Embodied Manifestation Condition chosen for them.
Anchor / Fetter
Per the book, the range a ghost/spirit can travel is quite small ( Rank x 3 yards / 5 yards ). Familiars that are fettered or anchor can drift further ( 15 yards for both ), and they can stay away from their anchor / fetter for an hour at a time. After an hour, essence bleed begins as normal (they lose 1 essence per hour). Note that anchored/fettered spirits gain 1 essence per day for being in this condition (though still spend 1 essence per day to stay active).
This is a custom condition. While Embodied, a spirit becomes wholly part of the physical world. There is no way to remove the spirit from the physical world except for destroying it's body (corpus). When the familiar sustains damage greater than their corpus, their physical form "dies" as it would naturally die, but the spirit will go dormant. Dormant spirits will float near-ish their fetter, undetectable, until they've rebuilt essence equal to their corpus, wherein they spend 1 essence to reform a physical body.
While Embodied, a spirit is immune to exorcism and abjuration.
This is available to both ghosts and spirits. After this power is activated, the ephemeral may stay away from their anchor/fetter for up to 12 hours. If they are not back within range of their anchor/fetter after the 12 hours ends, the ephemeral immediately goes dormant.
At present, Fate's Harvest is only using the Numina found in the GMC book, starting p. 228.
Ephemerals must be manifested to blast things in the physical work (or in Twilight to blast things in Twilight). Treat this as a firearms attack for calculating defense, armor, etc.
This numen is resisted by Resolve + Supernatural Tolerance. On failure, the target gains a temporary derangement called "Obsessed". While under this derangement, the becomes obsessed with a mission that is psychically and mystically implanted by the Ephemeral. For a number of days equal to the successes rolled, the character is will attempt to achieve this mission. They will not put themselves in obvious danger, or avoid commitments, but it is a constant distraction. While pursuing their mission, the characters gains 9-again (+roll/9) on all rolls. While doing anything besides that, the character is highly distracted, and loses 10-again (+roll/0).
Rapture is not in use.
Q and A
How do you kill a Spirit/Ghost?
Ephemerals have a health rating (Corpus). This works just the same as health for anything else (and they taking bashing, lethal, agg damage). If an Ephemeral is materialized, they can be hurt like anything else. While they are in Twilight, they can only be hurt by their bane, by other Ephemerals of the same type, and by specific types of magic that state they can affect Ephemerals in Twilight.
Banes: Banes are solid to ephemerals, even while in Twilight. Banes can be used as weapons where appropriate (such as a pure iron fire poker). While materialized, contacting a bane causes one aggravated damage per round it remains in contact, and damage dealt by a bane is aggravated. While in Twilight, it is the same, but damage is lethal.
Anchors/Fetters: If an anchor or fetter is destroyed, the ephemeral immediately starts to bleed essence (1 per hour). Likewise, if an anchor/fetter is exposed to a bane, the ephemeral suffers as if they were exposed to it. Note: This does not apply to familiars.
Essence: Ephemerals must spend 1 essence per day to remain active. If they cannot, they go dormant. Ephemerals with an anchor/fetter will remain as tiny motes, drifting near their anchor/fetter until they have gathered a point of essence to awaken. Ephemerals without an anchor/fetter will drift back into the Shadow, or into the Underworld, where they will remain until they gather a point of essence to awaken.
Exorcism (and Summoning): Exorcism is a long, intricate process that involves altering the Conditions that made an Ephemerals presence possible. Summoning is the act of creating those conditions. These both require an ST. To summon a fire spirit, an occult would burn rare materials, keep a fire going for days, remove all traces of water from a special space. This will make it very easy for a fire spirit, which would sense these conditions from afar, to come and manifest. Controlling that same spirit is extremely difficult, and more often involves bartering than any actual means of command. Generally this means using bans and banes as threats, and create the appropriate essence as bribes. For a ghost, this can be even more difficult, but is generally the same. Find the ghosts bones, spend time anointing and praising them, etc.
Abjuration: Abjuration is much more straight forward. This allows an occultist to temporarily suppress whichever Condition allowed an ephemeral to exist in the area for one day. During this time the ephemeral will face essence bleed, they will be unable to materialize, and they may ultimately go dormant and be forced back to the other side. Familiars will automatically return to their anchor/fetter when the day has lapsed. An abjuration is a particularly powerful invocation of one's own personal will, generally stylized in whatever religious or occult tradition the person has been trained in. Roll Resolve + Composure vs Power + Resistance. If the manner of ritual and reason for the abjuration supports one's Virtue, add 2 dice. If it supports one's Vice, subtract 2 dice. Additionally, add/subtract the following based on Integrity: 10: +3, 9: +2, 8: +1, 6: -1, 5: -2, 4: -3... etc. An abjuration generally takes hours.
How do I track my familiar's essence?
Honor system! Familiars automatically spend 1 essence per day to stay active, and gain 1 essence per day by being anchored/fettered. If your familiar is using a lot of essence, make sure to do an appropriate amount of essence-generating activities (such as remembering your ghost's life, or laying out in the sun for a sun spirit).
Which Numen are allowed?
We are only using the Numen from the GMC book, p. 228.
Do I need to clearly state I have a familiar, in case someone else can see spirits/ghosts?
No. We will assume that your familiar "stays outside" while you are in a scene, unless you have that spirit taking part in the scene. You may NOT retroactively say your Truth Spirit has been here listening the entire time. State OOCly if your spirit is near.
Do Embodied Familiars 'ping' as Spirits?
Yes. If someone has See Spirits, or Unseen Sense: Spirits, or Contract of Spirit, or some other ability that lets them see spirits in Twilight or sense their presence, they will notice your Embodied Familiar is a spirit.
I can see spirits in Twilight, can I also...?
Touch them? Generally speaking, no. Most powers will outline exactly what the power lets you do. Generally, this is see, hear, and speak to. At player/STs discretion, smelling an Ephemeral is just fine (particularly if it has a particularly strong smell). These powers do not grant the ability to understand a spirit/ghost (spirits can learn human languages but speak First Tongue, ghosts generally speak whatever they spoke when they died), nor to physically interact with a spirit/ghost, unless stated that they do. To be clear, the Thaumaturge's See Spirits does not allow the Thaumaturge to touch (or be touched by) a Spirit in Twilight.