In many tutorials (incl.
Alcasts) for the Dwarven Ebon Mount it is told that this lead drops off the
Brass Hatchling Boss inside the Mtharnaz Group Delve, located in the Craglorn Zone.
Most tutorials (except uesp.net) tell nothing about The Skillful Seamstress, a giant spider in a cave nearby.
I tried many times the dwarven spider, but only its natural "sister" has dropped the lead.
For anyone who didn't know and was keeping to the tutorials....
PC EU (PL): 14 characters. ESO player since 06.08.2015. Farkas finest quote: "Some people don't think I'm smart. Those people get my fist. But you, I like."