Riddles of the undead

[Gerner]

Hi

I am running a campaign where some of my villains are working to resurrect Myrkul. To mix things up I need some riddles.
I have used this previously with great success but do to time issue I would love to get some riddles relating to Myrkul and a riddle on how to enter “The Vault of the Dead” currently locked with a lich hiding inside and manipulating the outside world.

Thanks for your help :)