The Fifth Abyss is ruled by Queen Baba Yaga, but there is also Queen Lolth there too. Baba Yaga is a daughter of the Chaos Mother, who seems to have appeared around the same time that Ereshkigal and Itzpapalotl did. Lolth is her daughter, but I have been unable to find any rumours as to Lolth’s sire.
Lolth is the Queen of Spiders. She is the foundation of many legends of evil spiders. The Ungoliant of Tolkein’s worlds is almost certainly a daughter of Lolth, which is ironic considering Lolth’s name actually appears in the Lord of the Rings as a daughter of Ungoliant.
The stories I have heard tell that the only non-spider on the whole of the Fifth Abyss is Baba Yaga, and that is only because she has a truce with her daughter, allowing her a small domicile, which is kept spider free.