Been following the manhwa since the webnovel days, so I can list them off the top of my head. The obvious one is Cale Henituse, our protagonist who just wants to laze around but keeps getting dragged into world-saving schemes. His internal monologue versus his external stoicism is the best part.
Then you've got his immediate crew: Choi Han, the overpowered swordsman from Korea who's intensely loyal; Raon, the adorable and supremely powerful six-year-old dragon who loves calling Cale 'weak human'; and On and Hong, the cat siblings who are actually ancient powers in cute forms. They're the core family unit.
The antagonists and allies blur together quickly. There's the White Star, the main big bad trying to awaken ancient powers for domination. Then important figures like Rosalyn the genius mage, Lock the wolf boy, and Eruhaben, the ancient gold dragon who becomes a grumpy mentor figure. The manhwa does a decent job introducing them, but you get their depths more in the novel.