The main character is of course the great mage who returns after 4000 years. There could be a young apprentice - type character who becomes his protege and learns from him. And there may be a powerful wizard or witch who is in charge of the current magical order and has a conflicted relationship with the returning mage, seeing him as both a threat and a potential asset.
I don't know for sure as I haven't read it. But surely the great mage himself is a main character. There might also be some current mages in the world he returns to who play important roles, either as allies or antagonists.
In the 'great mage return after 4000 years novel', the central figure is the mage who has been away for such a long time. Besides him, there might be characters like the leaders of the magical guilds in the present time. These leaders would have different reactions to his return. There could also be a group of adventurers or researchers in the magical world who cross paths with the returned mage and get involved in his story. Maybe there's a character who holds the key to some mystery related to the mage's past and their encounter helps to unfold parts of the story.
Chapter 504, ", How strong will the Alliance Fleet be after 4 years?", is the clearest early answer because a shaky connection becomes usable in the plot. It opens with The Empire doesn't favor aircraft carriers, but Gu Hang has no... and closes on As long as the patrol ship manages to fire off all the firepower it....
Chapter 142, "Demon Infestation Mission III", is the clearest early answer because it turns Damien's situation into a concrete plot event. The chapter turns that into something concrete by moving from Damien stood in the decayed clearing, his flaming sword casting... to The griffin had remained still until now, watching the battle with....
Chapter 155, "Battle In Westmont III", is the clearest early answer because the buildup finally cashes out in a real clash. It opens with In that brief moment of vulnerability for Damien, Fenrir and Cerbe... and closes on This ends now!" Damien shouted, his voice filled with determination.... The key payoff is that the danger stops being abstract and the conflict around the main cast becomes immediate, forcing the surrounding cast to react under pressure.
Chapter 124, "Battling A Grade Two Mana Beast II", is the clearest early answer because it turns Damien's situation into a concrete plot event. Early on, The fight with the Obsidian Drake raged on, its thick, scaled body.... By the end, One claw caught Fenrir mid-leap, sending the Monstrous Wolf flying....
Chapter 482, ", you made the right choice", is the clearest early answer because it turns Imperial Tax's situation into a concrete plot event. Early on, Through the virtual image of the Star Speech phone, Gu Hang saw the.... By the end, The wear and tear on the road would be immense.. Inside the broader faction conflict storyline, the chapter closes with "However, the method of retention can't be for me to keep it directly.
Chapter 27, "Burning Through Essence", is the clearest early answer because it turns Burning Through Essence's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Damien thought for a moment before coming up with a feasible solution... and follows through with Burning through Essence barely served as a means..
Chapter 466, ", I've had enough already!", is the clearest early answer because it turns Green Skin Orcs's situation into a concrete plot event. The chapter gives readers a real answer by opening on Or rather, the war had never actually ended. and ending on The United Fleet was slightly larger than that of the Green Skins,....
Chapter 469, ", Great Victory for Temir!", is the clearest early answer because it turns Skyburn Torpedo's situation into a concrete plot event. The chapter turns that into something concrete by moving from Some wanted to retreat, it was obvious that the battle was lost. to If they dispersed their forces, they would be intercepted and driven....
Chapter 436, ", Seven Horses Return to Allegiance", is the clearest early answer because it pushes Baishuo Star into a new phase or setting. The setup is The number of inspector officers assigned to each planet is not..., but the pressure keeps building through Among them, a certain presence is the military inspector officers..
Chapter 253, "The Town Inside The Barrier", is the clearest early answer because it turns Damien's situation into a concrete plot event. The chapter turns that into something concrete by moving from Damien remained still, his sharp blue eyes fixed on Lizella, watching... to The second guard, a gruff-looking man with sharp eyes, was less.... What makes it stick is that the chapter closes with Their conversation ended there, but Damien's thoughts didn't stop.