Etruscan tomb painting develops a figure under the closely related name Charun who has little in common with the placid Attic ferryman beyond the name: he is shown armed with a heavy hammer, blue skinned or otherwise monstrous, and functions as a violent death demon who may strike down the dying rather than simply carry the already dead across water.
Scholars treat the resemblance as a borrowed name attached to a distinct Etruscan figure rather than a straightforward import of the Greek boatman. Dante's Inferno gives Charon his most influential afterlife in Western literature: in Canto III he refuses to ferry the still living Dante, is overruled by Virgil's authority, and the poem builds him as an old man with eyes of burning coal who beats stragglers into his boat with an oar, an image Michelangelo later echoes in the Last Judgment fresco in the Sistine Chapel.
Modern Greek folklore folded the ancient ferryman into Charos, a figure of death itself who wrestles the dying on a threshing floor and carries them off on horseback, a considerable shift from a minor underworld servant with no cult of his own into folk religion's personification of death. In this later Greek folk form Charos is often depicted mounted rather than seated in a boat, riding down the living on horseback across open country, an image found widely in modern Greek folk song laments and one that owes as much to later folk imagination as to anything in the Classical sources this entry otherwise describes.
Sources The Religion of the EtruscansNancy Thomson de Grummond and Erika Simon (eds.) with The Divine ComedyDante Alighieri, Encyclopaedia Britannica (online academic reference)Encyclopaedia Britannica editors