The deformed sword is a bizarre weapon Emrys obtained from the hand of an abyssal back in the Boundary between Level 1 and Level 2 areas in the fragmented Cosmic World.
Back then, Emrys realized that the deformed sword is no ordinary sword, it is a weapon on the same level as the Sun & Moon Blade. This sword could swallow the Mist of Abyss (dark energy from the dark river) to strengthen itself. Not only this, this sword was likely the most dangerous weapon a person could use against an abyssal, because it can swallow everything an Abyssal has, including its energy, body, blood, and soul. [Ref. Ch - 172.]
Emrys was not powerful enough to use either the Sun & Moon Blade or the deformed sword. Both these weapons were inside his body.
Sun & Moon Blade was inside his Cosmic Essence Core. On the other hand, the deformed sword used to rest on the surface of the Dark River inside his sea of consciousness.
