Oneirurgy

Oneirurgy- known in some traditions as dreamweaving, dreamsculpting, or lucid dreaming - is a branch of high magic which deals with the manipulation of dreams.

Sleep

Sleep is a physiological process which occurs in the majority of creatures. In lower animals, it is assumed to have a purely physical function related to recuperation following exertion; in sentient beings, it is commonly believed to have a spiritual purpose of some kind. Many cultures see dreams as metaphysically important - or, at least, as having the possibility of such metaphysical importance - though the specifics vary; the Volsangans, Ald and Balthans, for example, believe that dreams can contain messages from gods or ancestral spirits, whilst the Tevashi and many Orcs from the khanates believe that dreams are primarily a source of inspiration from within, a conduit for thoughts and memories which are generally hidden from the waking mind.
It is notable that despite being ensoulled sentiment beings, elves neither sleep nor dream in the usual fashion. Whilst this is a trait that modern elves share with their eladrin ancestors, it is notable that it is for the most part not shared with other fey. This is not infrequently used by the Teriani to argue that elven souls are qualitatively different to those of other sentient creatures - be they Fey or not - in the service of their doctrinal claim of elven primacy; and by some non-elven groups who use it to justify negative views towards elves. The precise reasons that elves are unable to sleep or dream are poorly understood; some claim that the ability to dream was stolen from the elves along with their immortality, others that it was willingly sacrificed in a time of dire need, and others still that it is simply a natural part of elven existence that has always been and always will be. Many scholars suspect that the elven disconnection from the realm of dreams is somehow related to the Shattered Forest, and perhaps to the Great Gates - though what the nature of this connection may be is unclear.

Lucid Dreamers

Whilst in principle almost anyone can be taught to gain a measure of awareness and control over their dreaming mind, mastering oneirurgy takes a certain combination of creativity and force of personality, along with a lot of practice and a willingness to delve into some of the most unknown and alien parts of the psyche. The first step on this path is said to be to master the art of controlling one's own dreamscape - a state known as "lucid dreaming".
Elves are, for the most part, unable to utilise the methods of oneirurgy without significant magical assistance, though some of the meditative techniques used by oneirurges can be applied to enable psychic projection into the Shattered Forest.

OOC Mechanics

Lucid Dreamers have access to the following feat:

Lucid Dreamer
Prerequisite: Charisma 13 or higher

You gain the following benefits:

• Increase your Charisma score by 1, to a maximum of 20
  
• You gain proficiency in either Charisma or Intelligence saving throws.
  
• You are capable of projecting your consciousness into your own dreamscape whilst asleep whilst remaining fully in control of your dream, and have the ability to broadly shape the environment of your own dreamscape, creating landscapes, objects, or other images as you wish.Your dreamscape collapses into formless chaos when you awaken, unless you have some magical method of preserving it, and must normally be rebuilt from scratch.
  
• You have advantage on saving throws against the "dream" spell, and any similar effects that would affect your sleeping mind.
  
• You remain peripherally aware of your physical body whilst in the dreamscape. As an action, you may attempt to wake yourself up by making a Charisma ability check at DC 15.
  
• When you enter your dreamscape, you may take a number of other creatures with you equal to twice your charisma bonus (minimum of 1). All creatures that wish to join you must be willing, and be under the influence of a substance that empowers the manipulation of dreams, such as dreamsap. Creatures that do not sleep cannot be brought into the dreamscape without additional measures.

Dreamwalking

The Journey Inward

Oneiruges describe the realm of dreams - which they refer to as the Shadowlands - as existing alongside the material realm, in a similar manner to the Periphery. These two concepts are often confused by those who are not well-versed in planar geometries, but they are not entirely equivalent. A simple explanation that is sometimes given is to refer to the shadowlands as existing "inside" the physical world in some manner, whilst the Periphery exists "outside".
Unlike the relatively structured layers of the periphery, the shadowlands is typically described as a roiling sea of half-formed thoughts, emotions, and fragmented images, immersion in which is deeply corrosive to memory and one's sense of self. It is into this sea that most who dream will inevitably plunge, to later awaken with only the most vague and fragmentary of memories of what they experienced in their dreams. In contrast to the periphery, time and distance are essentially arbitrary notions within the shadowlands, and their ever-shifting geography cannot be mapped onto the material world in any consistent way - though experienced lucid dreamers do speak of an underlying order in which "emotional proximity" can be considered in certain ways akin to distance.
Sentient minds that enter the shadowlands instinctively attempt to make sense of the swirling confusion that surrounds them, and by doing so are able to force a semblance of order onto the sea, creating bubbles of pseudo-reality in which some notion of logic hold true. It is within these bubbles, known as dreamscapes, that mortals experience their dreams, influenced by a combination of forces from within and without. Whilst all minds are capable of stabilising the currents of the shadowlands to a greater or lesser extent, lucid dreamers are among the few who are able to do so consistently and with intention - though other methods such as the Dream spell are capable of achieving similar effects.
As well as individual dreamscapes, there are a number of distinct regions that are sometimes reported within the shadowlands that those who have explored the depths have sometimes encountered; these include such places as the Void Below and the Dreaming Depths.

Dreamscapes

Dreamscapes are sometimes described as being akin to islands of stability within the churning depths of the shadowlands. A dreaming mind inherently solidifies the formless unreality around it, but when they awaken their dreams immediately dissolve into formlessness. Whilst lucid dreamers are capable of consciously stabilising their dreamscapes whilst them inhabit them, their dreamscapes are no more persistent than those of others, and require magical methods to sustain them beyond the waking of the dreamer.
A dreamscape that is designed to exist independently of the mind that dreams it must be constructed around a core of spiritual power, known as a "seed" - this becomes a persistent point within the churning sea of shadows that is unchanged by the rolling tides, and which anchors the dreamscape in conceptual space. The destruction of the seed will inevitably cause the dreamscape to rapidly disintegrate, dispersing anything that was within it across the shadowlands.
The simplest option in this regards is often for the creator to act as the seed in their own right. This however has certain disadvantages - the most notable being that the dreamscape becomes in some ways metaphysically identical with the dreamer, who can be targetted by magic or harmed via damage inflicted to the fabric of the dream. A somewhat more secure method involves the creation of a "foundation stone", using an enchanted crystalline focus to which the dreamer attunes like they would to any other magical item. The method of constructing such a foundation stone is not especially difficult, but acquiring the crystalline substance which becomes the focus is substantially more difficult, as such crystals are only to be found in the Dreaming Depths.
It is said that some dreamscapes, empowered by particularly potent foundation stones or other forms of powerful magic, are capable of outliving their creators, and exist autonomously within the shadowlands. What might exist within these abandoned dream-realms, and how they may be found, is unclear.

The Journey Outward

Though extraordinarily difficult, it is in principle possible to traverse the barriers between the shadowlands and the periphery. There are said to be a number of ways in which this can be achieved; the most well-attested to is to pass through the twisting pathways of the Shattered Forest, though to do so is fraught with great danger. Another method is to pass through certain portals which are said to lead from more-stable regions of the shadowlands into areas of the periphery which share some conceptual resonance with them - though the location of such portals, and the method of accessing them, is a well-guarded secret indeed.

OOC Mechanics

• Lucid dreamers (who have taken the relevant feat) can enter their own dreamscapes at will when then sleep. Others can only do so with outside assistance.
• A lucid dreamer is capable of bringing a number of willing creatures with them equal to twice their Charisma bonus, minimum one. Familiars (and similar creatures with a strong spiritual bond to an individual) can be brought through automatically if the person to whom they are bonded travels into a dreamscape.
• A dreamer, lucid or not, who enters a dreamscape can choose to manifest phantasmal versions of any non-magical equipment that they wish to bring with them. This equipment is mundane and without any special properties (such as being made of silver it is not possible to manifest complex technological devices as phantasms through this method.
• A dreamer, lucid or not, can manifest any magical items that are in their possession, provided that they are attuned to them (if relevant such items will retain their full powers within dreams - however if lost or destroyed within the dream, they will lose their functionality in the waking world until the phantasmal version is recovered.
• Lucid dreamers can attempt to apport objects (magical or mundane) into or out of their dreams, though this is difficult. It requires a Charisma check at DC 15 for a simple non-magical object that fits within the palm of the hand, and significantly higher for larger objects or those of a magical or complex nature. Under normal circumstances, only one object can be apported in or out of a dream per attempt. An apported object brought into a dream from the physical world vanishes; one apported from the Shadowlands physically manifests in the dreamer's possession. It is possible to steal magical items from other dreamers through apporting them into the material world; if a phantasm of a magical item is apported into the material world, the original immediately fades into a mass of shadows and vanishes.
• Most dreamers cannot awaken of their own free will, but will do so naturally after some hours have passed, or if they are injured or shaken awake in the waking world. Lucid dreamers maintain a peripheral awareness of their physical body and surroundings, and can attempt to awaken as an action by making a DC15 Charisma check.
• Dreaming beings, lucid or not, generally take all damage within the Shadowlands as psychic damage. Entities which are fully manifest there take damage as usual. In contrast to the risks of psychic projection into the Periphery, under most conditions dreaming beings reduced to zero hit points in the Shadowlands automatically stabilise, falling into a deep sleep.