Looks like the Russian is returning https://www.youtube.com/watch?v=VrWNl8grkrU
I don’t know who this is, but it looks like Lux Interior, singer for the Cramps and a personal hero.
Romulan senator, manipulated by Captain Sisko and Garak to dupe the Romulans into helping Starfleet fight the Dominion. He wasn’t himself successfully manipulated, but his subsequent death (by Garak) was suspicious enough to get the job done.
Sisko doesn’t like it at all. But… he can live with it.