There were a number of things Northern had not began to explore about DiY, not because he couldn't but because he didn't want to.
At first, his plan for that certain feature of the system was to use his to create an undefeatable arsenal of void summons, it was the reason.
That alongside what he would be able to accomplish with soul forge. Northern was confident in the now-seemingly thousand ways for him to get stronger.
Hence, he decided to first mastering the forge, after which he was going to copy talents, upgrade them and then come to inspect the new void summon entries.
Then after all that was done. His plan was to begin to use the other souls around to forge power gears for his arsenal.
Then with the newly the creation ability of the void, he would create new permanent clones of himself with different personalities and sources of strength and for one of the incredibly amazing things DiY could do…