From Introduction:
The magus (plural magi) is an arcane caster of a tradition dating back to human civilizations only dimly remembered today. The first magi were the fire priests who led the worshipping people of desert coasts that mistrusted the gods. As the leaders and scholars of their people, the magi were free to study the depths of arcane sciences. They pushed their abilities to the limit, using all of their mental attributes to further their mastery of magic. Today, the very term for common arcane manipulation, magic, is borrowed from their title but few know that the magi still exist.
Magi are spellcasters above and beyond all else. Their closest counterparts are wizards but they tend to be less adventurous and do not bother with binding familiars as wizards do. A magus treasures the chance to focus on their research that isolation brings rather than create companionship. Additionally, while many wizards treasure their role as item creators, magi prefer to research spells. Magi respect discipline and are comfortable with wizards and psions despite their differences. Magi consider
wizards distracted and psions limited but nonetheless compatriots. Clerics are respected but their allegiances with gods are mistrusted and druids are admirable but…odd. In contrast, the lack of formal processes around wilders, bards and sorcerers make them wild at best and dangerous at worst.