أَوْ يَمُوتَ كَرِيمٌ
Or a generous man may die.
“Yamūta” is a present-tense verb occurring in the syntactic connection following “aw”; “karīm” is its nominative subject and is formally indefinite. This wording presents a “generous man” as though a distinct figure has come into view.
Rhetorically, that karīm is extracted from the speaker himself. The grammatical subject and rhetorically extracted counterpart are different analytical dimensions: one identifies syntax, the other explains the figure.
If the referent were an independently existing third person, the tajrīd reading would not follow in the same way. The context points to the speaker's self-praise.