Horn of the Abyss is an unofficial add-on to Heroes of Might and Magic III. It's created as a whole by game fans. Therefore, it can bring to mind another unofficial fan add-on - In the Wake of Gods - or one of many its modifications, but the difference is in project's nature.

Unlikely to above, Horn of the Abyss is to be a classic add-on, recalling original works of game creators, that is Armageddon's Blade and Shadow of Death. Instead of many news, changing game to a large degree and giving fans loads of modding functions as scripts language, HotA relies mainly on further game development, that is new units, artifacts or towns with minimal effect on game's mechanics.

In contrast to the vast majority of fan projects, in HotA Crew - a team involved in the project - occur people which are experts with their field. Instead of graphics from other games or found on the Internet, we have completely new works made by artists by theirselves. Instead of parts of various monsters put together, we have units which are made in whole 3D techniques. Plot is deliberated by the series experts, the mapmakers have a big experience in their job and the coders do their best to erase all errors which appear by interfering directly into the game code. What's interesting is that nobody pays those people for that - they do a good job only as their passion.