Hexblade - cleannrooster/Spellblade-Next GitHub Wiki

Hexblade invaders will come after you after a while, you will know that they are focused on you when you receive an ominous message about your magic being noticed. Simply keep using magic to get them to come after you. Eventually, a dapper fellow will approach you and demand that you pay the magic toll, at which point you can either oblige him, ignore him, or kill him. Ignoring or killing the Magister will make him summon more of his friends nearby and they will attempt to kill you for a minute, before they pack up and leave. Magisters can drop Spellblades, the Hexblade, and Prismatic Effigies--as well as Missive from Magus, which is a bit of a lore hint for the Magus fight.

If you want to summon Hexblade Magisters instantly, you can simply use an Offering to the Hexblade.