In early phases of first manga, the stories are self contained and has little connection with each other. In that phase, the tone and atmosphere tend to the light-hearted and episodic. The author's drawing dramatically improves after volume 5. The plot becomes much more refined as well. After volume 10 or so, the plot becomes really profound, deep, and heavier on continuity. The scale becomes quite large, with whole nations going to war and dragon(s) which can destroy the world.
