“Heroes of Might and Magic V: Tribes of the East”

Well, it's not Lina, is it? =)))

That's more likely. According to the storyline, she comes from the Sokolov family, and in Heroes 5, there's a hero named Duncan from the Fortress faction, and his biography states that he's the last of that family. We can assume that Lina is his daughter. Therefore, she could very well be included in this expansion.