Rituals can be performed by anyone with access to the Arcane or Religious ability list. They can be used to create items, gain new abilities or for just role-play reasons. Rituals are only limited by the scale of the things Characters perform them for.
Characters with the Arcane or Religious abilities may lead maximum of 2 rituals per an event. Characters with the skill Lord of Order/Chaos may lead up to 3 rituals instead.
Any character with a magic ability can contribute to as many rituals as they want.
To perform a ritual, the character must have a Referee present. They must activate the ritual and then utilise between five to ten minutes for their performance. This performance may include anything, but must be relevant to the objective you are trying to achieve. Other characters may help with the ritual and each will count for one contribution of power, except Sorcerers who will count for two. It is important that as part of the ritual you make it clear how many people are contributing power, highlighting any sorcerers extra contributions.
The ritual is marked of relevance, entertainment value and contributions of power, so it helps to have a few characters helping in any ritual. After the ritual is complete, the character may collect their result from their Referee. Players are advised to notify a Referee well in advance about when and where they want to perform the ritual in order to receive the best results.
What can be done by Ritual Magic
Ritual Magic is wild and variable and can bring about great boons, or great destruction. It is advisable to talk to the Head of Rituals if you are unsure if your planned outcome is possible, they will be able to advise you to some extent, although please make it clear if you are asking an OC mechanics question or an IC question.
There are a couple of types of magic that are known to not be possible:
Chronomancy is one of those. Time travel has never succeeded in even the most powerful of ritual circles, and indeed has a tendency to kill everyone participating. As such it is banned by the Guild.
Necromancy is a contentious subject. While the school of magic itself is neither impossible or illegal, there are some subtleties within that. Bringing someone back from the dead is impossible, the soul appears to pass on when the body dies. Any attempt to bring someone back has ended at best with a new Risen, who does not possess the soul or memories of the departed, or at worst in calamity and death. At present, creating new Risen deliberately is outlawed by the Grand Alliance so will have IC consequences if an attempt to do so is discovered, whether the attempt is successful or not.
Mental control magics that give direct control over another person have also never been achieved and are impossible. There are many theories on why this is, as even attempts to copy the Strigoi Ghoulification ability have not been successful. Roleplay effects such as an inclination to loyalty, a desire to remain calm under pressure or similar have been achieved, but only very rarely. (Note, this is an OC rule for player safety and welfare reasons)