The R.R.W. Deihu is a Ha'apax Advanced Warbird and the flagship of the Romulan Republic in 2409, prior to the role being passed on to the Tulwar-class R.R.W. Lleiset. In that year she is commanded by Temer, and later Nadel.
- “Tradecraft”: The Deihu - along with several Republic and allied ships - support the player during a battle with the I.R.W. Aethra's fleet.
- “Blood of Ancients”: In 2410, allied forces regroup aboard the Deihu after engaging Iconian forces at New Romulus and Lae'nas III.
Charva in the Deihu's brig.
- The Deihu is likely the inspiration for the playable Deihu-class Science Command Warbird.
- According to the glossary in Duane's The Romulan Way (first printing), "deihu" means "elder" or "Senator."