Astral's specialty
The specialty is a gameplay element for all heroes in Heroes of Might and Magic III, Heroes of Might and Magic V, Might & Magic: Heroes VI, Might & Magic: Heroes VII, and Heroes of Might and Magic: Olden Era.
Specialities are a unique bonus that each hero passively provides. For example, in Heroes III, Aeris increases the attack and defense of his pegasi and silver pegasi, Mullich gives all his creatures +2 speed, and Sephinroth generates a crystal every day. Some heroes share specialities, such as Pasis and Monere that both specialize in psychic elementals and magic elementals, but have different Secondary skills to differentiate them.
Most campaign-only heroes borrow a specialty from a regular hero. For example, Tarnum from the Heroes Chronicles missions uses Crag Hack's Offense specialty while he's a Barbarian. Some campaign heroes have unique specialities however, such as Dracon's ability to upgrade magi and monks to enchanters.