Heroes are main characters of the Lord of the Rings universe that appear in the Battle for Middle-earth games, for each faction. Heroes have very high health (among other elevated stats), and can fend off many regular units at once. Some very special powers are also given to heroes, which are often connected with the character's role in the stories. Most Heroes are real Lord of the Rings characters that J.R.R. Tolkien came up with such as Glorfindel, Azog, the Mouth of Sauron, King Theoden, and many others. Some heroes (like Gorkil the Goblin King or Berethor) are added by the game makers, though not created by Tolkien.
In The Battle for Middle-earth II and its Expansion pack, custom heroes can also be created by the player. Heroes are summoned from the faction's Fortress - and if a hero dies, he/she can be revived and recruited back.
The Rise of the Witch-king expansion added "hero-horde" units for each faction, which are elite and powerful units just a step down from heroes.