>>7525308Dooku is his only name. His family is House Serenno (as in the planet is literally named after them) so that's the closest thing he has to a last name. His brother gets introduced as Ramil of Serenno at one point, so I think if you absolutely needed to give a full name it'd probably just be Dooku of Serenno.
Legends had Dooku as a last name but for some reason never revealed his first name, even though several named family members appeared in the Agent of the Empire series. Incidentally a lot of stuff about Serenno from that comic is re-canonized, mainly lore and locations.
