An inheritance wasn't hard to make for a divine being. Noah's inscription methods didn't suit that type of structure, but his mental waves were enough to alter the environment to his needs.
Inheritances generally needed a secret location, trials, and rewards. Noah could use the separate dimension for the structure, and he had already planned what to give to his heir. He only needed to create the tests to complete that project.
Noah would normally fill the place with powerful magical beasts, but the world had a shortage of living beings. He could use his ability to communicate with those creatures to create packs and force their reproduction, but he preferred to use another approach.
The many experiments with the living weapons had taught him how to create living beings. Noah could fill the separate dimension with an army of creatures that followed his orders instead of training living beings for the task.
