καίνυμαι the pluperfect commonly functions as imperf.
to surpass, excel, ἐκαίνυτο φῦλ᾽ ἀνθρώπων νῆα κυβερνῆσαι he surpassed mankind in steering, Od.; ἐγχείηι δ᾽ ἐκέκαστο Πανέλληνας he excelled all the Hellenes in throwing the spear, id=Od.; ὁμηλικίην ἐκέκαστο γνῶναι surpassed them all in knowledge, id=Od.: esp. in part., δόλοισι κεκασμένε excellent in wiles, id=Od.: τέχνηισι κεκασμένος Hes.; φρουραῖς κέκασται is well furnished with, Eur.