Caeneus

In Greek mythology, Caeneus (Ancient Greek: Καινεύς, Kaineus) was a Lapith hero of Thessaly and, in Ovid's Metamorphoses— where the classical model of a hero is deconstructed and transformed— originally a woman, Caenis, daughter of Atrax. Such warrior women, indistinguishable from men, were familiar among the Scythian horsemen too (see the entry "Amazons") and survive among Albanian traditions as the "sworn virgins" (virgjinesha,).

In Apollonius of Rhodes' Argonautica, where there is no inkling of his transgender, he was briefly noted as the great father of a lesser son, Coronus, who sailed forth among the Argonauts. The striking mythic image of this hero is that, indomitable through his more-than-human power, his enemies the Centaurs resorted to driving him into the ground with timbers.

they could neither force him to yield, nor yet dispatch him,
but unbowed, unbroken, he went into earth down under,
crushed by a shattering hail of heavy pine trunks.

Read more about Caeneus:  Myth