If you want to continue the Demon King Hero series to see which manga to choose, I suggest you first understand the relationship between the series and the manga. The anime series was created by the same author, and the manga was adapted from the anime. Therefore, if you want to continue watching the animation, it's best to choose the manga version first. If you want to start watching the series from the manga, I suggest you choose Demon King's Hero's Blade. This was a manga created by the Japanese manga artist Hiroko Hamauno. Four volumes of manga had already been released. The manga's storyline and character creation were similar to the animated version, and the manga's graphics were more detailed. If you're not satisfied with Demon King's Hero's Blade, you can look for other manga works. The other works in the series included the Devil King's Hero's Chain, the Devil King's Hero's Flower, the Devil King's Hero's Sword, and so on. Each of them had their own unique storyline and style.