If you're looking for anime similar to Hakkenden: Eight Dogs of the East, you might like these titles. All recommendations are made by Anime-Planet users like you!
Upon trying to save a friend from bullies, Shibuya Yuuri finds his head in the unlikeliest of places -- the toilet. Like a flash, Yuuri is then inadvertently sucked in, transporting him somewhere else! In this unfamiliar world of flying skeletons and magic, he is informed by a group called the Mazoku that he is to be the next Maou -- ruler of the kingdom! With harrowing and embarassing situations ahead, can our hero swallow his pride and lead a war against the common people when he can't even tell the difference between a slap in the face and a marriage proposal?
Both are adventure/fantasy/action type anime. Main characters are teenagers with demonic powers. Both incorporate humor throughout, but it does not take over the show (Kyo Kara Maoh! being the more comedic of the two). Also, they tend to play with yaoi themes, although neither are full-blown yaoi-- they just tease about it. The primary reason if you like one, you may like the other, lies in the beautiful and loveable character design and overall feel of the story.
In order to bridge the gap between humans and youkai, The Ministry of Spirit Affairs was formed. Military man Kei Agemaki is assigned to the new unit and seems to be the ideal candidate. He’s charming, polite, and a complete gentleman, but there’s just one problem: he’s absolutely terrified of spirits! When he arrives at the new headquarters, Agemaki is partnered up with a cute, yet brash, youkai named Zakuro. Now the unlikely pair must work together to solve the region’s spirit-related problems to help improve relations between humans and youkai, and maybe help Agemaki overcome his crippling fear while they’re at it.
Both series are historical fantasy/drama that involve spirits and monsters. Both MC's are stubborn and spirited kids who have close bonds with their spirit friends. Everyone is good-looking and there are lots of swordfights, spirit power battles etc.