hello @LadyJJ,
Firstly, I want to say thank you for downloading the game and I am so happy to know that you are enjoying it! Defeating Fernando and the legendary 7 is an absolutely huge undertaking and I am very impressed that you’ve defeated them! To answer your question, all remaining tasks that you need to do once you go to the underworld are in the underworld. There is an NPC in town who’s daughter was kidnapped, she needs to be saved, you need to prove your self worthy in the underworld arena also, those are some of the tasks that will lead to getting the key to the castle of darkness. Your character should be called Narmita, If her name is Narmi then she has most likely already transformed. Hips transformation can be found in the starting country library. In the snowy continent there is a semi-big tree in the overworld. If you walk into it you will find an angel that will tell you the location of the veryones transformation!