After obtaining the fragment of the Red-Handled Sword, Aiwass began preparing the ritual to summon Merlin.
In fact, there wasn't a ritual like this. But when Aiwass had previously met Merlin, Merlin had given him an invocation to summon himself, which was akin to exchanging phone numbers.
Although Aiwass was not a Great Sorcerer, his skill in rituals was far from ordinary.
With this invocation serving as the core of the ritual, Aiwass could directly construct a ceremony to summon Merlin:
The key intelligence was that Merlin was a "Knight," a "Half-Demon," and also a "Mage."
Because of this, the key numbers for summoning Merlin were Wisdom as four, Strength/Authority as seven, and Transcendence as eight. Combined with the information that Merlin liked mysterious, beautiful things and traveling, he enjoyed gourmet food, beautiful women, and fine wine, and that "Merlin" meant "Prime Minister" in some places, the materials for constructing the ritual were thus determined.