Ritualism
All races may learn the secrets of Ritualism, and tie themselves to the symbolic and ritualistic manipulation of the Realms and Forms. Homunculi may never start a Ritual, though they can learn the mechanics and rites, and assist others in performing rituals. Ritualism requires a physical spell book to be in front of them when starting and performing any rituals. Ritualists also have need of a focus item, which stores their spells after the rituals have been performed. This focus must be placed on the spell book when the spell is imbued in the focus, and must be touched when the spell is released from the focus. Some rituals do not require a focus. Ritualists may work together in order to complete their rituals, and many form themselves into cabals. Cabals are groups of three to nine ritualists that all share the same ideals and goals. Many cabals are bound by magical rules that strengthen them as a unit, but at the cost of a specific weakness. Cabals are often secretive and mistrusting of other ritualists. Since a spell book is knowledge and power in the world of ritualism, cabals fighting or dueling over spells is a common, if unseen, occurrence. Ritualists are welcome in many areas of the land, and mistrusted and even hunted in other regions.
You can learn more about ritualism in Chapter 15 of the Rulebook.