So. I was thinking about suggesting a Senkaimon -- the means by which Bleach shinigami travel between their world and the world of the living. Now, obviously that wouldn't really be a thing here, so would it be possible to have that tweaked to where the "worlds" it could travel between were the Echo barriers? Or would that be changing it too much for it to be Echo-able?

Also, should that be workable, there are technically two "paths" through the Senkaimon. One takes people through a dangerous path called the Dangai (an intermediary pathway), and one that is quick and easy (basically just a room to pass through). The quick and easy way would necessitate a later Creature Echo on Toushirou's part before any character -- including himself -- could use it, but I suppose the question here is whether having both paths would be within the limits of the Echo, or whether they'd count as two separate places and therefore only one would be eligible.