Ushio to Tora by Fujita Kazuhiro
You know the drill, the anime is great albeit rushed, so here is the full award-winning manga in English for your enjoyment! All 33/33 vols, translated by various groups and a six chapters long gaiden volume.
You know, I still sometimes wonder what happened to ardneh, the group that translated most of the UtT... they were going to continue Karakuri Circus (this was years ago), and - poof - they just disppeared, utterly and completely. Dead? Are scanlators just humans after all.. a scary thought.. Anyways, enjoy the manga!