Heroes of Might and Magic III: Horn of the Abyss (abbreviated as HotA, russian: «Рог Бездны») is a Russian fan-made full scale add-on for Heroes of Might and Magic III: The Shadow of Death, designed to continue the classical Heroes III add-on series of RoE/AB/SoD.
The good thing is that it can now be played online, if there are those who want it, it will be great.