Gensou Maden Saiyuki is an anime and manga series by Minekura Kazuya. If you're familiar with the chinese story "Journey to the West", then Saiyuki will be very familiar to you. Genjo Sanzo, Cho Hakka, Sha Gojou, and Son Goku are bid by the gods to journey west to stop the revival of Gyuu-Ma-Ou, a youkai sealed by Prince Nataku. The people who are trying to revive Gyuu-Ma-Ou have caused all the youkai (monsters) to become agitated and attack humans. Sanzo and company must go the west and stop the revival of Gyuu-Ma-Ou to prevent more chaos.

As of right now, I have up to episode 22 of the anime. There is a lot more and I'm always updating. I have up to chapter 14 of the manga (that's the middle of volume 3, I think). I think that there are at least 10 volumes of manga but I don't have the rest scanlated.