While Libra might look like a woman, he's actually a man. He is voiced by a woman Fire Emblem: Awakening, but I wouldn't mind a feminin male voice either.
Libra is a kind man who presents as stoic and perpetually composed, rarely getting angry or emotional and always keeping his wits about him. While polite, he has a number of odd habits that confuse others, and as indicated by his fate in the ending he has a soft spot for and likely wishes to protect children due to his own past.