Daskinor appears to be afflicted with a textbook case of paranoid schizophrenia, delusions of grandeur, and catatonia. In reality, these mental illnessness are rather banal. I recognize the symptoms because my older brother has all three.
Lets mix it up a bit. Instead of the “mad king” trope based on real world mental illness, let’s make Daskinor fantasy insane.
When Daskinor attempted to open a door to the netherworld, he failed. He did open a door to somewhere, however. The Far Realm touches on the material plane of Athas in a way that the outer planes do not, and it was to the Far Realm that Daskinor opened the doorway. This doorway wasn’t a portal in the traditional sense of one that could be walked through, rather it was a gaping hole that allowed bizarre reality of the Far Realm to seep into Eldaarich, and into Daskinor’s mind.
Daskinor is not insane. If anything he has transcended beyond the feeble understandings of the other Sorcerer Kings. What do they know of impossible geometry or the reality of two contradictory states both being possible simultaneously?
Daskinor spends hours a day starting into the breach, allowing the Far Realm waves wash over him, as he communes with both beings that exist yet do not exist, possible yet not possible in accordance to the logic of the Far Realm.
Daskinor’s strange orders to his government have nothing to do with insanity in the conventional sense, and everything to do with producing a butterfly effect that will produce an outcome that seemingly has nothing to do with the strange order (such as when he banned psionics for a time). The psionic ban allowed the breach to extend the flow of Far Realm energies to spread all over Eldaarich, which is now having interesting consequences. Thus successful, Daskinor rescinded his ban on psionics, making him seem more insane. Of course, no one could possibly understand Daskinor’s point of view… Yet. As the Far Realm slowly influences the people of Eldaarich they will recieve the same lunatic insight as Daskinor himself (but to a lesser extent as Daskinor, being an advanced being, is able to comprehend much).