The new world was just a world of light, nothing existing there but light and Noah found it difficult to keep his eyes open. The light hurt his eyes as well as burned away at his mind. It was an unpleasant experience.
But relief came soon enough, his powers merging with the space around him. He approached the tree in the centre, looking at its huge trunk and intimidating power. He extended his hand, the core at ready and inserted it into the small hole in front of him.
He had done his part, now it was up to the world tree and Keito's spirit to fight this fight. The other had to come back because Noah was waiting for him. He had broken the biggest taboo of all, maybe even allowed the 'body' access to this place but he did not mind. If it was for Keito, then he did not mind even burning this world.