There were various valuable treasures; the previous adventurer’s equipment that we got our hands on looked dull compared to the vast number of powerful magic items here. Amidst this treasury crammed full of items, in the innermost part, was a mummy with a strange left arm shining in silver, enshrined in a throne.
Returner called this mummy its master. This probably means that it was Velvet.
Returner's time was about to run out and before that he wanted to tell us something.