In feudal Japan, evil spirits known as mononoke plague both households and the countryside, leaving a trail of fear in their wake. One mysterious person has the power to slay the mononoke where they stand; he is known only as the Medicine Seller, and he vanquishes the mononoke using the power of his Exorcism Sword. However, in order to draw his sword he must first understand the Form, Truth and Reason of the mononoke. Armed with a sharp wit and keen intellect, the Medicine Seller wanders from place to place, striking down the mononoke in his wake.
Mushi are another form of life which live parallel to our own natural world. The source of many myths and superstitions, they exist according to their own natural laws, and can be both beneficial and dangerous depending on circumstances. Ginko, a traveling mushishi, investigates and helps out wherever the mushi have become a problem. Yet Ginko himself is marked by the creatures he researches, and he carries the weight of his past with him.
Both Mushishi and Mononoke focus on a mysterious travelling protagonist who helps solve problems caused by supernatural phenomena. While Mononoke has a darker tone to it and each plotline is longer than Mushishi, if you enjoyed one it's worth checking out the other.
At first glance, Kimihiro Watanuki appears to be a normal high school student; but little do people know that not only is Watanuki able to see spirits, but he's also a magnet for them! One day, after being chased by one such spirit, Watanuki happens upon a strange building. There he meets a mysterious witch named Yuuko, who claims she can get rid of his ability to see spirits - for a price: Watanuki must work as her housekeeper until he has paid off the cost of granting his wish. Now Watanuki's eyes are being opened to an entirely new side of the world as he assists Yuuko in her work, all while balancing the housework, his schoolwork, and most importantly, ensuring that Yuuko is never out of sake!
Though xxxHolic has far more comedy, both these manga focus on the world of the supernatural and the effect that spirits and youkai have on the human world. While Mononoke focuses more on human folly, and xxxHolic on fate, it may be worth your while checking out one if you liked the other.