Lord Ethan couldn't do anything in that situation. Noah's dark matter made sure that Heaven and Earth never restored the connection with his centers of power. The expert couldn't summon his energy to break free from the dark world, so he continued to burn.
'His cultivation level is decreasing,' Noah noted in his mind while inspecting his prisoner.
Night wasn't severing Lord Ethan's connection with Heaven and Earth, but the ambition continued to taint his existence. Noah stole pieces of his law every time the expert died, and his cultivation level inevitably fell during the process.
Noah benefitted a lot from that procedure. Solid stage experts contained a lot of energy, but they were hard to find and kill. Instead, his tactic allowed him to reuse the same cultivator over and over again, providing him with a nigh-endless source of power.
'I can deal with the insane requirements of my body like this,' Noah happily confirmed in his mind while turning toward the battlefield.