The earliest recollection I have of Cane (as part of the HLU) comes from a single note Vid passed over to me sometime in the Spring of 2015:
The story calls for a sensei-type character. Think Stick, think Master Splinter--that's where my mind is going.
Basically, that's how he came to be. Obviously, from Origins onward, he is much more like Stick than Splinter--a shit talking loudmouth--but he also carries a lot of subtextual weight that feels wholly unique to him. He fits this universe like a glove, hence why I opted for giving him a more prominent role in Origins (and subsequent stories too, obvs).
The Unmourned are a completely new, post-reboot invention. Cane required a formidable foe--or a group of foes!--hence why a group of ninja criminals and assassins seemed more than fitting at the time of putting Origins together. He plays a pretty important role during City at War and Origins respectively. He is also to appear in Ash and Water as an important part of that engine.
--IS