Loptr Laegjarn

Loptr Laegjarn is the divine sword prophecized to be created by Surtr by combining his sword Lævateinn with Freyr's former sword Sumarbrander.

It is the most powerful divine weapons that will be created in the Norse Pantheon, fated to be the final bane of the ash tree Yggdrasill, as Surtr shall use this sword to lit the World Tree on fire during the events of Ragnarök.

Abilities
As it is only prophecized, many of the sword's abilities still remained unknown. However, it is said to be capable of creating golden flames of absolute destruction that will burn away all life and destroy the entire nine worlds of the Norse cosmology, as well as the World Tree Yggdrasill supporting it, with only a single swing of the sword.

According to the Norn Skuld, the golden fire generated by the sword is destined to be powerful enough to set the entire Northern European region ablaze for hundreds to thousands of years non-stop with just a single spark from the blade.

Trivia

 * The Loptr Laegjarn is inspired by the Noble Phantasm of the same name from Fate/Grand Order.
 * Unlike in FGO, this is an actual physical sword instead of an attack using the combined sword like in the game.