Spoilerish (Labyrinth of Tigers)

What exactly do I need to do to get this, cause being stomped by mount nomad didn’t seem to do it for me… Is there some additional trigger?)

you need to have died and passed on a legacy at least once

But apparently endings that aren’t technically death (or at least not immediately death) don’t count.

Does that unlock it for all subsequent captains, or just ones on the same lineage?
Like, if i make a throwaway captain, they die, and then retire my good captain, will her heir have the labyrinth unlocked?
edited by Impish Axile on 2/10/2015