There are only 26 episodes, the last 4 are OVA (Original Video Animation) that are extensions to the series.
Yes, there is only one season and no amount of petition will bring about a 초 because of the ending, the work that went it to it, and the fact that the original author would like to be done with it.
There are 26 Episodes and 4 OVA Episodes. The list of Episodes are: 1.City Of Howls 2.Toboe, Who Doesn't Howl 3.Bad Fellow 4.Scars in the Wasteland 5.Fallen Wolves 6.The Successors 7.The 꽃 Maiden 8.Song of Sleep 9.Misgivings 10.Moon's Doom 11.Vanishing Point 12.Don't Make Me Blue 13.Men's Lament 14.The Fallen Keep 15.Grey 늑대 - OVA 16.Dream Journey - OVA 17.Scent of a Flower, Blood of a 늑대 - OVA 18.Men, Wolves, and the Book of the Moon - OVA 19.A Dream of an Oasis 20.Consciously 21.Battle's Red Glare 22.Pieces of a Shooting Star 23.Heartbeat of the Black City 24.Scent of a Trap 25.False Memories 26.Moonlight Crucible 27.Where the Soul Goes 28.Gunshot of Remorse 29.High Tide, High Time 30.Wolf's Rain Hope it helped^.^ If not, then I am sorry for bother you.