It is also the most draining, requiring 7 stamina points to use.
For a long time, the effects of this spell were largely unknown. Only one Sorcerer ever managed to cast it successfuly, but he was never seen again afterwards.
The option for the player to cast this spell appears in the final Sorcery! book, The Crown of Kings. When the player is imprisoned alongside the Jann the Minimite, the player is given the option to attempt to cast a spell to aid in his escape. But in the earlier encounter with Jann in the Shamutanti Hills,the player learns that in the presence of a Minimite, most magic is neutralised and will not be effective.
However, when the option to cast ZED is selected, the player discovers that the spell is so powerful that even the presence of the Minimite cannot negate it's effects. Jann elaborates by saying that the spell allows the caster to travel through time and space itself. By casting this spell, the player is able to travel back in time to before being captured by the Archmage of Mampang and thus defeat him once and retrieve the Crown of Kings.