τὸν ἴδιον κίνδυνον ὑποθείς → at his own risk
V. νέρτερος, P. and V. χθόνιος (Plato but rare P.), or use P. and V. ὁ κάτω, ὁ κάτωθεν, V. ὁ ἔνερθε, ὁ κατὰ χθονός.
the nether world, subs.; P. and V. ᾍδης, ὁ.
nether darkness: Ar. and V. ἔρεβος, τό, V. ζόφος, ὁ.