The Romulo-Vulcans were hybrid descendants of Vulcans and Romulans after their Unification. By the 32nd century, they formed a distinct faction within the society of Ni'Var and were trying to forge a new path for themselves. They had their own regions on the planet; after the Burn, insurgencies arose in these regions that had to be quashed by the Vulcans.
For the T'Kal-in-ket invoked by Michael Burnham in 3189, Peer Shira represented the Romulo-Vulcans in the Quorum. (DIS: "Unification III")