The Ovon is the home of the Neke, one of the most influential Chitin Queens clan-groups in all of Top. Inside, it is a maze of imposing halls and tiny, hidden nooks, linked by a tangled maze of tunnels and corridors. The Ovon itself is alive, with new rooms and structures grown rather than made, and extends through extradimensional space to include open-air gardens and portals to other areas of Top within its dome.
Amanita has made the Ovon her home for the past couple of years, and was its de facto ruler before the Neke returned from their mysterious and lengthy absence (see Return of the Neke). Her current position is unclear.
Twin calls the Ovon (her) home as well. (Her) role in its society is unclear, beyond "ruler's pet". Perhaps "regent", in the rumor-wrapped absence of Amanita.
Okyno and Atcinna are among the first generation of the returned Neke, bent on restoring their palace to its ancient glory.
The Sphere Theatre is located within the Ovon.
While not an actual extension of the Ovon, the Temple of Kelil can be reached from a dimensional gate within its courtyard.
Inspirations:
I struggled with its external appearance for a while and finally settled on "a cross between the Taj Mahal and a radiolarian", after flipping through a Dover book of illustrations by Ernst Haeckel ([1] [2]).