1. https://www.wowhead.com/ru/npc=93127
2. Не работает menu option: "Kayn, tell me what you know about Mardum."
3. Открываться gossip_menu:
Eons ago, Sargeras created Mardum to imprison demons. He also created the Sargerite Keystone to lock them away.

But when the Titan decided to burn all of creation, he shattered Mardum, sending its fragments hurtling throughout the Twisting Nether. Thus was born the Burning Legion.

Sargeras safeguarded his keystone on this particular fragment. It's a 'skeleton key', allowing access to any Legion world. It's also the key to Lord Illidan's plan for the Legion's destruction.
4. BFA x11