A ritual is an esoteric and complex spell that anyone can cast. It takes much longer to cast a ritual than a normal spell, but rituals can have more powerful effects.
When you take charge of a ritual, you are its primary caster, and others assisting you are secondary casters. You can be a primary caster for a ritual even if you can’t cast spells. You must know the ritual, and the ritual’s spell level can be no higher than half your level rounded up. You must also have the required proficiency rank in the skill used for the ritual’s primary check, and as the primary caster, you must attempt this skill check to determine the ritual’s effects. The primary skill check determines the tradition. Rituals do not require spell slots to cast. You can heighten a ritual up to half your level rounded up, decided when the ritual is initiated. A ritual always takes at least 1 hour to perform, and often longer. While a ritual is a downtime activity, it’s possible—albeit risky—to perform a ritual during exploration with enough uninterrupted time. A ritual’s casting time is usually listed in days. Each day of casting requires 8 hours of participation in the ritual from all casters, with breaks during multiday rituals to allow rest. One caster can continue a multiday ritual, usually with some light chanting or meditation, while the other casters rest. All rituals require material, somatic, and verbal components throughout their casting time.