The divine armor didn't disappear after the quasi-rank 7 Eternal Snake created that giant layer of protection. Noah could sense the divine aura flowing out of that immense amount of ice, so he could guess that the creature was somewhere inside that silver shell.
The already big Snakes' leader had transformed into a giant mass of ice that had its shape. That sight would normally scare away most of its opponents, but Noah didn't let the view of that new ability discourage him.
'I can still kill it,' Noah thought as he stared at the creature.
He had prepared his attacks while he waited for the transformation to end. He wanted to be ready for any ability the Snake decided to deploy, but he didn't expect that the creature would help him.
The ice created by the creature's silver liquid had gathered into one place now. Noah wouldn't need to kill the Snake multiple times anymore. Defeating it in that new form would be enough to win that battle.