Famous for inventing many different elemental seals used by the genie binders of Kelesh, as well as the artifact known as the bottle of the bound, said to contain 666 fiends within, including their master, the daemonic harbinger Zelishkar. (Though it should be noted that the Sulesh had no hand in binding the daemons to the bottle, rather its original prisoner, a particularly mighty and ancient efreeti, aided The Pharaoh of Forgotten Plagues, in filling the now-empty bottle with the fiendish army).

The point being that is that Sulesh was easily one of the most famous (or infamous if you happen to be a genie or other powerful outsider) conjurers in Golarion’s history, who believed that mortals could and should bind the power of other planes to their will, regardless of consent from the otherworldly beings involved.

Naturally, after his death, the genie binders who followed in his footsteps studied his work heavily, hoping to someday replicate and even surpass his most powerful binding seals. This led to the practice of calling upon his spirit directly in hopes of gleaning more information, and so the practice of mediums channeling him began, ironically putting at least some aspect of the great conjurer in the same sort of position as the genies he once bound, though unlike the genies, Sulesh is still afforded the freedoms to reject and vacate a host, like any spirit.

In order to establish a pact with Sulesh, one must travel to Kelesh or any establish conclave of genie binders, and prove one’s knowledge of genies, taking an oath to never release a genie from its bonds, even those the swearer had no hand in binding.

Of course, in your setting, this spirit may simply be a famous conjurer of a different sort, and have different backstory and requirements to call upon.

 Valuing the superiority that comes with controlling summoned beings, a common taboo that Sulesh demands of those who channel him is to not suffer foes to use that same power, targeting summoned opponents exclusively before moving on to their summoners.

Rather than allow the medium a choice in what magics they learn from their spirit, Sulesh instead grants them access to a whole slew of basic summoning spells.

Sulesh does offer some unique abilities, though, namely, being able to help speed up the casting of said summons a few times a day, and, if the medium is willing to grant him further control, cast a summoning spell a little bit more powerful than what the medium is normally capable of.

Looking to make a sometimes-summoner out of your medium? Pursuing this spirit might be the way to go. Admittedly, the Golarion-canon requirements involve being party to binding outsiders against their will, but regardless, there is potential to be had there, character-wise. It’s even possible to learn to actually use planar binding spells using this spirit, but it requires the medium to be high enough level to be able to cast any spell on the sorcerer/wizard list through the unchanged archmage powers. I recommend a support build if you plan to primarily use this spirit, buffing allies and summons while staying back.

 The standards of morality in Kelesh and that part of the Golarion setting being what they are, and Sulesh being who he was, I feel that those mediums that pursue this spirit cannot be 100 percent good without changing the backstory of the spirit. Such an alteration would likely associate the spirit with a different conjurer, one that believed in making consensual bonds with outsiders, rather than enslaving them.

  Curzira the Caller was one of the greatest wyvaran magic-users to ever live. Some say she was even able to summon dragons to do her bidding. While none alive have matched this feat, Curzira lives on in wyvaran tradition, and as a spirit, answering the call of mediums who prove their skill and trust in their summoned allies.

 Mediums who channel Vorkul, Chainer of Spirits have reported that the domineering conjurer’s spirit no longer answers their summons. An investigation of his grave site reveals that the complex has become infested by festrogs and even more terrible undead, disrupting the spirit’s connection with their defiling presence.