Cocytus Frost Aura

Thus, he unleashed his aura.
It was a skill derived from the Knight of Niflheim class — [Frost Aura]. This special ability damaged and slowed the foe through the use of extreme cold temperatures. At full power, it could even engulf the Lizardmen spectating from the sides.
So he had to suppress its power.
He had to narrow its radius and reduce its damage.
“This ought to do it…”
A wave of freezing cold expanded from Cocytus, instantly filling a radius of twenty-five meters across.
The temperature plummeted upon exposure to the intense cold, and the very air seemed to groan.

- Overlord; Vol 4; Chapter 5