What is ชุดจักรวาลร่วม?

Not usually. Many shared-universe romances are written so each book works as a standalone with its own central couple and arc. Reading in order can add extra layers—recurring characters’ backstories, callbacks, and larger plot threads become clearer—but it's not always required to enjoy a single book.

A direct series (or trilogy) follows the same protagonists and a continuous plot across multiple books. A shared-universe series instead focuses on different protagonists within the same world; the continuity is in the setting and side characters rather than one continuing storyline.

Yes—one of the hallmarks of shared universes is moving supporting characters into starring roles. This approach lets authors explore different perspectives in the same world and gives readers a satisfying payoff when a fan-favorite side character gets their own story.