This production is a gorgeous piece of work. Taking inspiration from classic period dramas and Japanese theater, the world of ONMYOJI is mysterious and poetic. The story retells many classic folktales (which probably won't be familiar to general Western audiences) around an original overarching narrative concerning the fate of the Imperial Capital in the hands of supernatural powers. The star of the show, Mansai Nomura (Seimei), has an incredible handsome, crafty presence throughout. Hideaki Ito is also pretty funny as Hiromasa, the bumbling nobleman who enters into a close friendship with him. And of course there's Hiroyuki Sanada who turns in an excellently strident performance as the enemy onmyoji. The music is also quite memorable too; a combination of traditional Japanese-style overtures and other times, like a suspenseful large budget fantasy movie. There are a lot of special effects, but I think the real appeal is the interaction between the characters. The writing was greatly helped by the fact that they had the original author on board as a screenwriter. Instead of just making a film adaptation of his books, he craftily created an original narrative (one that's easy for the film to handle) that weaved in several references to his written works. Overall if you like Japanese folklore and the elegant, meditative style of Japanese theater, you'll love this movie. But if you're expecting a gigantic budgeted, action packed epic in the vein of the LORD OF THE RINGS films, this will probably not suffice (don't let the positive remarks on the English packaging fool you).
PS: Because of the wildly different directions both franchises take, many people fail to realize that this series and DOOMED MEGALOPOLIS (TEITO MONOGATARI) series are "cousins". The latter started the contemporary widespread interest in "onmyoji" (yin yang diviners) while this series (written only 3 years after) took the same subject matter and greatly expanded its appeal. The main character here is the ancestor of the villain and the elderly hero in DOOMED MEGALOPOLIS. Likewise, if you like DOOMED MEGALOPOLIS, I would recommend you watch this movie for more context about the mythology. If you like this movie, I would recommend you watch DOOMED MEGALOPOLIS for a totally different handling of the same subject matter.