I prefer the idea that Damar, as a character in his own right, has his own story that intersects with Dukat's on the freighter.
In "Return To Grace," we see Damar as a competent, dutiful soldier who seems eager to fight, but there isn't any evidence of the admiration and deep loyalty to Dukat that becomes clear in Damar later on. He seems loyal to Dukat as his commander, but that's about it. Of course, we don't see much about Damar except him doing his job until the last act when he seems pretty excited about taking over the Bird of Prey.
Dukat's quest to disobey the Central Command and wage a one-ship war against the Klingons may have struck Damar as something noble and even romantic (in the sentimental and fantastic meanings of the word), especially with them becoming renegades and dependent on each other and their crew for nearly a year (or thereabouts). Damar's admiration and loyalty to Dukat would have flourished in such a heady atmosphere.