spell for Tekumel.
The Faithful Messenger
Type II, Generic ritual spell, usable by sorcerers dedicated to Belkhanu, Sarku and their cohorts Qon and Durritlamish.
As described in 'The Taupe Scroll of the Thaumaturge Bel', the casting sorcerer and one other person take part in the ritual sacrifice of an animal, though occasionally a human is used. From the remains of said animal two bones are chosen and one each is taken by the two participants. They can now communicate telepathically via these bones over any distance, and even through nexus points, across multiverses and potentially across periods of time as well.
The potency depends on the Psychic Ability of the sacrifice, since it is this soul that has to find a way through the skeins of destiny to carry the message to its target.
The victims vary, but animals known to be highly psychic are favoured. In Sokatis the local tiuni (domestic cat) breeds are known to be able to see demons, the Temple of Qon favour their guard tlekku (dogs), Belkhanu temples often use snakes, Durritlamish crows and other flying carrion eaters.
Roll Psy Ab for the sacrifice, any below 11 (or 60 is using EPT) is useless. Base potency is 1 and add +1 potency for each Psy Ab above 12, +1 more per point above 15 and +1 another per point above 17. For EPT take PsyAb-60 and divide by 4 to get the bonus.
A given pair of people may have no more than one pair of bone talismans in use at any one time, only the people involved in the original ritual may use them and they must remain within three metres of the owner to retain their potency. Usual practice is to make a bulla of an appropriate holy metal (copper for Sarku, gold for Belkhanu) to house it.
In EPT a sorcerer must already know the spell 'Medium' to be able to cast this one, and the recipient must know 'Medium' or 'ESP' to pick it up.
For Advanced EPT the prerequisite spells are 'Perceptions of the Energies' and 'The Blessing of the Planes' to learn, and 'Perceptions of the Energies' or 'Ascertainment' to receive.
Spell level/EPT caster level
4: Soul may carry messages totalling no more than the spell potency in words and only to a recipient on the same plane as the sender. Once the limit in words is reached the spell ends and the talismans revert to being mere bones. Range is impressive though, 3 to the power of potency in tsan. A highly psychic animal soul could take your message 59,000 tsan. Talismans remain useful for 1 day per power point times the numerological signfier of the deity of the caster - four for Belkhanu and Qon, five for Sarku and Durritlamish.
5: Soul may carry messages of no more than the spell potency plus 4 or 5 in d3 (ie potency 5 roll 10d3) words, depending on the numerological signifier of the deity it is dedicated to.
6: Soul may traverse a nexus point to deliver its messages back and forth. Loses 1 potency every time it does so though and requires a saving throw vs magic from the sender to succeed, so try and be as close to the nexus points as you can for sustained contact. Number of words goes up to potency in 1d6, and the talisman is useful for potency x 4d3 days for Belkhanu, potency x 5d3 days for Sarku. Physical distance within a plane can be up to 5 to the power of the potency in tsan. Enough to contact a moon from the surface of Tekumel.
7: Soul traverses multiple nexus points, losing 1 potency per transfer, but words are up to 1d8 per potency plus 4 or 5. Useful for most trans-planar travellers, but unfortunately useless in such dread places as the Unending Grey or getting messages out of the Blue Room. Can cover 7 to the power of the spell in Tsan, enough to reach other planets in the Tuleng solar system if within the same plane. Useful for potency x 4 or 5d6 weeks.
9: Soul can travel from anywhere to anywhere, distance no object, planar and time differences utterly irrelevant, and can transmit 1d12 words per power point plus an extra 4 or 5d12 before failing. The talisman is useful permanently until that message total is reached however. Getting a message in and out of some planes may require a save vs Magic on behalf of the message sender or recipient.
Other temples my have spells or magic items that have similar effects. For example the Temple of Thumis have rods made of sanctified ssar wood from a grove on an island beyond the edge of the world that may be bound together as pairs. What appears on one rod scratched in the script of Thu'usa also appears on the other. The Temple of Hru'u allegedly keeps strange glass plates in the catacombs of Hmakuyal upon which letters in a lost language of the ancients appear and disappear to the accompaniment of invisible chimes; it is hypothesised that they are bearing messages, but the knowledge of how to read them is lost.
There are two stones, one in a temple to She Who is Not Seen in Par in Pijena, the other sacred to She Who Strides the Ocean on the shore near Jorulu in Haida Pakala, and graffiti daubed on one will also appear on the other. These stones will only transmit obscenities however, and are solely used in ritual slanging matches between the clergy of the two deities.
It is a source of annoyance to the temple of Belkhanu that the Sarkuites get a bit more mileage out of this spell, but that's numerology and superior preservation techniques for you (the Sarku temple uses the same varnish as it does in making shines out of bone).
Using cats has its pros and cons. Mean GMs may rule that while a cat soul has superior Psychic Ability, it also has a 10% chance of getting lost on any given attempt at messenger transfer, or if a rival sorcerer finds out about this secret message stuff he can distract the cat soul by sacrificing fish or mice to intercept it.