The fusion was complete, but Noah's lungs needed some time to adapt to the changes in their structure and learn how to activate their new innate ability.
Noah couldn't even test his organs for the time being. He couldn't know if the forging were a success until his lungs stabilized.
However, his dark matter took care of them, and the incubators didn't affect Noah's lifestyle. It was harder to breathe with his lungs in that condition, but he didn't need air to survive.
Noah could only wait and hope that his dark matter would take care of any flaws in his new organs. He felt quite optimistic about the whole fusion, but his eagerness to test his new power made him impatient.
Luckily for Noah, he had plenty of things to do. He had completed all his projects, but there was still a world to save. He could also spend more time training since the packs on the surface needed to reallocate their forces to occupy the now empty lands.