While the titular event in God of War Ragnarok ends Kratos' Norse story, but it's very unlikely that the game will leave the Norse world completely destroyed.
2018's God of War is surprisingly open-ended, giving players the freedom to explore Midgard and other realms to their heart's content. While the game's main story and most of its levels are linear, various optional areas and objectives make the Norse adventure feel truly massive. Even after Kratos and Atreus have finished their quest to reach the highest peak in the Nine Realms, players are able to explore the game world to achieve 100% completion. Facing the overwhelming power of the Valkyries, completing combat challenges in Muspelheim and unlocking the secrets of Niflheim can provide many hours of additional adventuring after beating the God of War story.
The open-ended structure of 2018's God of War makes it very unlikely that God of War Ragnarok will end in the annihilation of the Norse world. The sequel looks to stick pretty closely to the last game's structure, which means that it will probably be comparatively open-ended. In order for players to go back and complete optional content after the story ends, the Nine Realms must remain at least partially intact following the events of Ragnarok. God of War Ragnarok's one-shot camera style, which is also being carried over from the last game, also makes it unlikely that players will be clumsily sent back to before the story's conclusion to clean up loose ends.
God of War Ragnarok Can Explore A Reborn World
While many fans speculate that God of War Ragnarok will feature Kratos' death, it's unlikely that Ragnarok and the end of the world will cap off the game's story. Norse myth actually details a period following the events of Ragnarok, during which the world begins to heal and certain mythic figures are brought back to life. The human survivors Líf and Lífþrasir are said to repopulate the world following the destructive events, while the Aesir gods Hoder and Baldur are resurrected and reed in the living world. Baldur's reappearance after Ragnarok is particularly notable, due to his role as the main antagonist in 2018's God of War. It would be fascinating if God of War Ragnarok explored this peaceful period following the destructive Ragnarok, perhaps as a contrast to the violent destruction of the Greek world in God of War 3.
It has been confirmed that God of War Ragnarok ends the Norse saga, but the narrative doesn't necessarily have to conclude with the complete destruction of the world. Mythic battles and widespread destruction can serve as the game's climax, but players could then explore a post-Ragnarok world to complete optional content and soak in the violent event's aftermath. This would allow God of War Ragnarok to remain open-ended while still delivering the destruction that fans are expecting.