For comics with different levels such as Battle Through the Heavens, Ultimate Martial World, and Douluo Continent, you can refer to the following suggestions: [1]"The Blade of Ghost Destruction": This is a ghost hunting themed story about the adventure story of the protagonist, Tanjiro, in order to save the humans who were attacked by ghosts. In the manga, there was also a hierarchical system similar to Battle Through the Heavens. The protagonist, Tanjiro, shuttled between ghosts of different levels and constantly improved his strength through battles. 2."Sword Art Online": This is a virtual reality themed story about the adventures of the main character Kirito and other characters in virtual reality. In the manga, there was also a hierarchy system similar to Battle Through the Heavens. Through continuous battles and increasing strength, Kirito gradually advanced to higher levels. 3 "The Attack of the Giants": This is a story about the battle between humans and giants. It tells the story of the adventures of the protagonist Alan and other characters in order to stop the invasion of the giants. In the manga, there was also a hierarchy system similar to Battle Through the Heavens. Giants of different levels had different abilities and attack methods. Through continuous battle and improvement of their strength, they could be promoted to a higher level. 4. Fate/stay night: This is a story with magic and war as its theme. It tells the story of the adventures of the protagonist, Emiya Shiro, in order to save mankind. In the manga, there was also a hierarchy system similar to Battle Through the Heavens. Followers of different levels had different abilities and characteristics. Through continuous combat and improving their strength, they could advance to a higher level. The above are some manga recommendations similar to Battle Through the Heavens, Martial Extreme World, Douluo Continent, etc. I hope they can be of help.