2174. Mixed Boundaries
The reason that Midnight was so focused on the manas and how she could sense it was simple. She was focused on it because she could feel the changes throughout Walker and her connections.
The bond that the two shared was sharing their senses to a degree along with some mana. While the pair had never utilized their connection to bring manas between them at large amounts, it had happened naturally for their entire relationship. The very same with Onyx's bond with them too.
However, because they had entered the elemental planes, there had been more manas around them at all times. Because of this, they had noticed that the manas flowing between them was growing even more than what they had been handling until now.