Abyssic?

Etymology of The Abyssic

a-byss
noun
1. a deep, immeasurable space, gulf or cavity; vast chasm
2. anything profound, unfathomable, or infinite: the abyss of time
3. (in ancient cosmogony)
a. the primal chaos before creation
b. the infernal regions; hell
c. a subterranean ocean

-ic
suffix
1. having some characteristics of (ex. sophomoric)
2. in the style of (Byronic, Miltonic)
3. pertaining to a family of people or languages (Slavic, Semitic)

Word definitions by www.dictionary.com.