There are two overall types of Adept in Geoza:   those with Magical Talent, and those with True Calling.  These are not exclusive categories.  It is possible for a Persona to have both Magical Talent and True Calling (such Adepts are known as Theurges).  Most Adepts, however, will have only one of these Background Aspects.
A Persona must have the True Calling Background Aspect to use any Origin which is the channeled power of a deity.  Geoza has a large and varied population of deities to choose from.
A Persona must have the Magical Talent Background Aspect to use any Origin which is not the channeled power of a deity.   Such Origins include Mana, Sorcery, Spiritism, Alchemy, Runes, and Necromancy.

Adept Skills

Origins may require additional characteristics as a prerequisite to their use.  The use of Mana requires the Manasense Background Aspect in addition to Magical Talent.  Sorcery requires the Insight Attribute.  And Spiritism requires the Sensitivity Background Aspect.  Alchemy, Runes and Necromancy have no requirements other than Magical Talent.  Some Deific Origins may have prerequisites.
All Origins are governed by an Arcane Lore - a Trained skill that rates how learned the Persona is in using that Origin.   Mana Lore, Sorcery Lore, Spirit Lore, Necromancy Lore, Rune Lore, and Alchemy Lore must each be learned by a Persona wishing to use the respective Origin.  Each Deific Origin has a Doctrine Lore skill that fills a similar function for that Origin.
One of the changes to the ARIA persona creation rules is that Personas do not purchase Omnessence skills with Interaction Points.  Because of the variety of Origins available to Adepts in Geoza, and because Personas may develop more than one Origin, it would be tedious and prohibitively complex to develop a set of Omnessence skills for each Origin.  Instead, in the Geoza system, each Persona capable of Omnessence use has one set of Omnessence skills that apply to any Origin the Persona can access.  A Persona's ability to Create is constant, whether that Persona is gathering and shaping Mana, or channeling the power of a deity.  The use of an Origin is governed and limited by the Configuration Might of the Origin, the configuration expertise of the Adept, and the Adept's rank in the governing Arcane Lore for that Origin.  The lower of these three ratings is the effective configuration might for the Adept.
For example, in the basic ARIA system, the lesser of the Configuration Might or the configuration expertise of the Adept is used to determine the limit of Omnessence use in that Origin.  Geoza adds the additional limitation of the Adept's Arcane Lore rank.  The effective Archetype or Dominion rating of an Adept cannot exceed the Adept's rank in the appropriate Arcane Lore.   Thus, if an Adept 's Creation skill had a rating of 7, and his Mana Lore was only rank 6, his effective Creation skill would be 6 for effects using the Mana Origin.  If that Adept also had a Sorcery Lore of rank 7, he would be able to use his full Creation skill for Sorcery effects.
Another change to the Omnessence rules in Geoza: instead of averaging the Archetype and Dominion in a configuration, and then squaring the result to determine the maximum Omnessence which can be used in a Paradigm effect, simply multiply the Archetype and Dominion together.   This produces the same range of capability overall, takes less effort, and results in a "smoother" progression of capability.  With this system, an Adept with Creation 5 and Energy 6 can use up to 30 Omnessence in an effect - greater than the 25 which an average '5' would give him, and less than the 36 which an average '6' would grant.
A Persona's starting ranks in the Omnessence skills are determined by the player during the Background Aspect step of Persona Creation.  For each rank of the Magical Talent Background Aspect which the Persona purchases during Persona Creation, 9 Omnessence Development Points are received.   Omnessence Development Points (ODPs) may only be spent to purchase Omnessence skills.  Any points not used in the purchase of Omnessence skills are lost.   The player may spend these ODPs in any combination she wishes for her Persona, purchasing the various Archetype and Dominion ratings at the development cost for Skills as listed in the streamlined Geoza rules.  If divided evenly among the various Archetypes and Dominions, a Magical Talent of rank 10 would grant an average of 4 in every Omnessence skill.  Such a division of points would result in an Adept of mediocre ability in every area, but no great skill in any one area.  Specialities within Omnessence skills may also be developed, either using ODPs or later using experience.  

Some examples of spending ODPs on an Adept with the Magical Talent Background Aspect at rank 10 (90 ODPs):
A Mystic Healer (specializing in Creation, Divination, Transformation, and Organic)
Conjuration 0 Flux 1
Creation 9 Organic 9
Destruction 0 Matter 1
Divination 9 Reality 0
Manipulation 3 Spirit 1
Transformation 9 Will 3
This arrangement provides excellent potential capability in the areas most important to healing (Organic) - Creation and/or Transformation in order to perform the healing effects, and Divination to diagnose illness or other problems.  Additionally, some points were spent in the areas of Manipulation and Will, which would give moderate capability when combined with one of the higher skills (Manipulation Organic, for example, would average to rank 6).  And minimal ratings in Flux, Matter, and Spirit give lesser ability in those areas as well.   Other combinations would be certainly be possible for the same concept, however.  Consider a Mystic Healer who heals the mind and/or spirit, as well as the body:
Conjuration 0 Flux 0
Creation 7 Organic 9
Destruction 0 Matter 0
Divination 7 Reality 0
Manipulation 4 Spirit 7
Transformation 7 Will 6
Such a Mystic has less ability in outside areas, and has fewer really high ratings (only Organic now has a rating of 9), but he has a wide variety of healing abilities now.  His organic healing potential is only slightly reduced (Creation or Transformation /Organic now averages 8 rather than 9), but he has added moderately high ability in Creation, Divination, or Transformation/Spirit at rank 7.  This healer also possesses moderate ability in Creation, Divination, or Transformation/Will at rank 6.  But this Mystic has sacrificed any ability in several areas in order to have several high ratings.  Of course, any of these ratings would be limited by the Mystic's rank in Mana Lore.  But the native potential in key areas will be very important to later development of the Persona.

Omnessence skills can be improved during the course of the Persona's adventures, but doing so is generally more difficult than with other other skills.  A Persona cannot develop Omnessence skills alone.  To improve any Omnessence skill, a teacher must be located who is willing to train the prospective student.  The teacher must have a higher rank in the skill being taught than the student.
This requirement creates several consequences in the game.  One major consequence is that very high skill ranks become much less common in Omnessence use.  There are likely no more than a few handfuls of Adepts who possess more than one rating of "10" among their Omnessence skills, for example.  An Adept who has even one skill at rank 10 was either born with incredible native talent in that area, or has studied under a great teacher (who was himself born with incredible ability, or studied under someone who did, etc.).
Another important consequence which follows from the first is that Omnis (organizations of Adepts who share common ideals, goals, or philosophies) become much more important to the long-term development of an Adept.   Omnis provide a means of sharing the knowledge of the talented few who possess high scores in various skills, as well as their experience and accumulated knowledge of other Arcane areas.  A lone Adept who belongs to no organization would probably never improve upon his native abilities.  For some, such as the Mystic Healer outlined above, this may not be important.  He has tremendous potential in the areas which are important to him, and would be able to develop his ability in healing to a high degree of expertise over time, without ever improving his Omnessence skills.  For others, who wish a greater range of ability, or who wish to improve their specialty areas even higher (to a '10' for example), finding training in that specialty may become a quest in its own right.
Legendary Adepts would acquire status among others, not for their ability to throw devastating balls of flame at their opponents, but because such ability means that they have a rare and thorough understanding of the Flux Dominion, for example.  And an Adept who has studied under a great teacher acquires some status as well, because he has had the opportunity to improve his abilities in the areas in which that teacher specializes.
Omnessence skills are developed at the same cost as Renown during later development as well as during Persona Creation.  IPs used to increase Omnessence skills during adventuring must be the result of training, as specified above.
Adepts who possess the True Calling Background Aspect, rather than the Magical Talent Background Aspect, follow the rules as listed above, substituting True Calling Rank for Magical Talent Rank.
Adepts who possess both True Calling and Magical Talent must select both aspects at the same rank, and purchase Omnessence skills using that rank, not the combined total.  Theurge Personas must balance these two aspects of their lives.