Ishtar (Lunar Veil)
The sorceress' temple
The Ishtar is a large biome generated by the Lunar Veil mod on world creation that is found right below world spawn.
The shadowy temple is mainly made of Ishtar Blocks. Spring Vines constantly generate inside the Ishtar. As well as many ambient cobwebs.
Ereshkigal can be found at the bottom of the Ishtar standing next to a large Pulsar Hole that instantly kills you. You need to give her Sigfrieds Photo Album to obtain the Voidal Passageway to summon the Supernova Fragment.
The Ishtar can only accessed after beating Zui The Radiance and her casting a spell so that it doesn't melt you when near it.
The Ishtar, similar to the Abysm gives the player a debuff which darkens all of the biome. This can be slightly improved if an Ishtar Candle is equipped.