Mordred's Hideout

In Astro Knights Island
Mordred's Hideout is where Mordred escaped imprisonment in the dungeon and continued his work, but when the King and Queen found out where he was hiding, Mordred escaped into space using a spacecraft he had not yet finished. A poptropican later discovers his hideout in the events of Astro Knights Island. Mordred hadn't been in there for a long time, which is why it is covered in cobwebs. He eventually found a new hideout.

In Super Villain Island
Mordred's hideout is apparently destroyed in the Binary Bard's mind, if you click on a torn portrait of Mordred, your poptropican will say: "I think this is when Mordred started to fall into madness.". There are two rooms to Mordred's hideout in the Binary Bard's dream.