Manannan

Manannan is referred to in a few more places than that. I don't remember if he was in G1-3, but in the pre-G4 storyline quest, using the How to Get on a Boat and etc keywords on citizens of Bangor brings up dialogue about him. Also, in G12, Legatus mentions him. When not in G12 and talking to Eabha, he will mention he is one of the many sons of Manannan mac Lir, (should we call him Manannan or Manannan mac Lir? Mac Lir indicates he's the son of somebody named Lir,) and he was seant there two collect the white bones of Falias. That would indicated the Falias Gatekeeper is also a Demigod or Lower-Tier God.

In the Korean Test Server for G16, there are items involving Manannan. Meaning he'll be mentioned again in G16. (The items are quest items, a helmet and a tear [rock].)