Hydrus
primeval god of waters who had, according to some sources, emerged from Chaos alongside Gaea
HYDROS (or Hydrus) was the protogenos of the primordial waters. In the Orphic Theogonies Water was the first being to emerge at creation alongside Creation (Thesis) and Mud.
The primordial mud solidified into Gaia (Earth) and with Hydros produced Khronos (Time) and Ananke (Compulsion). These two in turn caught the early cosmos in the coils, and split it apart to form the god Phanes (creator of life), and the four ordered elements of Heaven (Fire), Earth, Air and Sea (Water).
The Orphic Rhapsodies later discarded the figures the Khronos and Ananke, and have Phanes instead born directly from Hydros and Gaia.
The figure of Hydros was ultimately derived by the Orphics from Okeanos, the earth-encircling fresh-water river which Homer described as the source of the gods.
His early consort Thesis was likewise the primordial equivalent of Tethys.
[1]