Lir

Roma Mater (London, 1989) by Poul and Karen Anderson confirms on page 271 that, as their names suggest, the Ysan sea god, Lir, is indeed the father of the Irish sea god, Manannan mac Lir. This gives an even greater unity to Poul Anderson's historical fantasies. There are two generations of gods:

the father is active in the Ys tetralogy;

the son is a character in two of the five "Viking" novels, The Broken Sword and The Demon Of Scattery.

What is Lir's parentage? The vestals sing:

" 'Lir of Ocean, dawn-begotten...' " (p. 124).

A summary of the origins of Ys suggests that Lir as a deity might have pre-existed his association with the sea:

"Lir, whose cult was more ancient than colony or tribe, took unto Himself the awe and dread of the sea." (p. 212)

Manannan is humanoid (see image) whereas Lir, never anthropomorphized, is sometimes described as three-legged and single-eyed but only to evoke "...something strange and terrible." (p. 122)

Of the Ysan Triad, Belisama, "the Brightest One," incorporating Ishtar-Isis, is the most comprehensive. She:

leads Taranis back from the dead to reconciliation with Lir;
is present at the act of generation;
ts the triple goddess;
leads the dead in the Wild Hunt.

These are most of the functions of a deity?