Who is Jin?

After the victory over the Stacks, the royal troops occupied their territories. They destroyed all the representatives of the tribe and reached their main settlement. There, in the ruins of the sanctuary, they found an ancient lamp. The royal magicians determined the age — about six hundred years. They also opened the lid and released the one they called "jin". The creature does not fulfill desires. It sends curses.
 
The essence is simple: the one who rubs the lamp calls the name. Gin does not demand sacrifices, does not ask questions. He simply pronounces the name after the owner, and then whispers: "May you be forgotten in your affairs, may your hearth be empty." Three days later, the named person begins to lose his memory, then his loved ones die, and then he himself. No one survived Jin's curse for more than a year.
 
In the scrolls of the Stacks, jin was called differently — "our father who cannot die." It turned out that jin is the founder of the tribe. He was a great warrior who burned someone else's sanctuary and was cursed himself. He was tied to the body of Rogoz and left in the steppe without water. But he did not die, but became a spirit who took refuge from the steppe sun in a lamp. And now anyone who rubs copper gets not a servant, but the spirit of a vengeful, unhappy old man who no longer remembers himself.
 
But why didn't the Stacks use gin in the fight against Ericuria? Historians believe that it's all about the name of the king. He introduced himself as Sigurd the Third. But his parents named him differently, and only when he ascended the throne, he became Sigurd. The Stacks didn't know about it.