Magic

In Birthright magical energy is known as Mebhaighl. This is formed deep within the earth and also created by all living things, the energy of the earth and plant life. It typically flows in intricate patterns over the world along natural leylines, and can be pooled into great sources by a skilled wizard.

Natural leylines can cause the flow of mebhaighl to be particularly strong in some areas. This magical energy randomly causes unnatural things to occur such as drifting glowing lights, odd sensations, the unusual passage of time and the like. However, normally magical energy only manifests in some way when directed to do so by a spell-caster or magical beast.

Spellcasters can be of wizardly type - true mages who can channel and shape the vast reservoirs of mebhaighl formed within the earth and by plant life into source holdings, and magicians who can tough only the less stressful magics of divination, illusion and the like, and so on. In Birthright wizardly spell-casting is rare, and true wizardry is rarer still. Most Anuirean and Brecht realms have at most 1 or 2 true wizards. Elven and Khinasi realms have even more. They are at their rarest in Rjurik or Vosgaard due to wizard magic being less accepted in their culture.

The most common spellcasters are priests whose service to the gods enables them to wield magic. Their connection to this mebhaighl is not as direct as mages and magicians. Their diety grants them the ability to access this mebhaighl and may remove that access at will.

It should be noted that being a medieval setting, many of the folk of Cerilia would treat magic in a similar fashion to what we would call science (e.g. magnetism, gravity, cloud formation, storms, etc.). Wizards are likely considered to have power over them - regardless of the reality of the situation. With such levels of ignorance, a wizard's power is often more in the superstition directed towards them than in the actual spells they can cast. After all, a wise wizard never reveals the true extent of their power.