The most common spellcasters are Wizards and Sorcerers who use Arcane magic. Maguses, Shamans, and some Warlocks also use Arcane magic. But more on them in a bit. Arcane magic works by subtlety adjusting the balance between Order and Chaos that underlies our reality. The primary difference between Wizards and Sorcerers is in how they learn and cast their spells. Which most of you are likely already familiar with. But, for completeness and those who may not know. Wizards load spells into their minds with the mana attached and once the spell is cast it vanishes from their mind leaving room for a new spell.   Sorcerers on the other hand learn spells permanently (well simi-permanently. more on this in a bit) With the mana as a pool to be taped and channeled through the spell as needed. Wizards can take a Feat called Spell mastery that allows them to permanently learn a spell the way a Sorcerer does. And likewise Sorcerers can take a Feat called Spell Flexibility which allows them to temporarily learn a spell as Wizards do. Seeing the advantages of being able to do both some adventurers tried training both ways. This proved to be quite difficult as the two ways of learning spells are almost opposites. Which puts quite a bit of strain on the mind of the student. Which eventually lead to the development of the Magus class. Which is designed specifically to address that problem. Progress is somewhat slower than for students who follow just Wizard or Sorcerer paths. But those who choose Magus say that it worth it. Anyway moving on. The next most common type of spellcaster is the Cleric or Priest. Priest are typically those who stay in Towns and Cities taking care of their congregations. While the Cleric is out with groups of adventurers keeping evil beings away from civilized lands.  These spellcasters use Holy Magic provided by the Gods. Or Infernal magic provided by Demons or Devils in the case of Evil Clerics and Priests.  Typically their handling of spells is much the same as Wizards. With the spells they are likely to need being provided by the Being they serve.  Healing spells being a notable exception in most cases. These tend to be installed Sorcerer style and can be cast extra times by sacrificing other spells for the mana needed to do so. The difference between Good and Evil Healing spells is a side topic that I'll expound on more fully another time.   Just as I will cover Warlocks, Shamans and the rest a bit later in this series.  

Well, Good luck with finding any Demosidhe, Demosidhe Essence, or Demosidhe Hunters. As one might expect. Things that are from a time refered to as "The Forgotten Age" tend to be rather hard to find.  Slightly easier to find are spellbooks than contain Arcane spells that reproduce Dreamwalking abilities.  Well, most of the spells are Arcane, there are at least a few variations of these spells in Divine and Infernal formats. But as those spells are rarely written down in the first place I don't expect that you will find any of those.  Then again; Given Your "Talent" for getting yourself in to trouble...  

Snypiuer disregards ALL warnings and simply notes - May get "snippy" if used as fuel source.

There are forms of essence magic that would allow someone to drain Demosidhe essence and either consume it or embue an object with it so as to gain Dreamwalking abilities. Of course this would come with it's own risk. Those who hunt Demosidhe might mistake you for one or assume you are bonded to one depending on the type of magic that they are using for tracking them down. And on the other hand Demosidhe and those willing to bond with them would probably be able to tell what you had done as soon as they see you using your powers. And they would probably not be happy about it. And given their ability to create very realistic dreams... Would you want to risk finding out just how creative they might be about expressing their displeasure over your having eaten one ? So while I don't have any accounts of this being tried. I expect that at some point someone did;  and it probably didn't end well for them. Essence Magic is an interesting topic in its own right and I'll try to cover it in more detail somewhere else; assuming I haven't already.  

Are there any accounts of anyone "feeding" on or "harvesting" the Demosidhe to, simply, take their power, rather than partnering with them?