Emperor Frederik V was the Ottilian Emperor during the time when Siegfried declared himself Emperor in Middenheim, triggering the Age of Three Emperors. Siegfried made war on Frederik, and Frederik made war on the Elected Emperor in Nuln. It is unknown who the victor of this war was.
- Warhammer Armies: The Empire (8th Edition) p.9
- Sigmar's Heirs p.17