Surt, the king of the fire giants, bearing his sword that is hotter than the sun and will burn our world at Ragnarok.

Voluspa - Norse Mythology Book - Verse 52

“Surt fares from the south |  with the scourge of branches,

The sun of the battle-gods |  shone from his sword;

The crags are sundered, |  the giant-women sink,

The dead throng Hel-way, |  and heaven is cloven.”

Bellows Translation