Mithril (ミスリル) is a metal found in YGGDRASIL and the New World.
Mithril was a metal often used to strengthen armor alongside orichalum. It was a very expensive material. One would be able to afford a mithril full plate armor once they reach orichalcum rank. A mithril rank, which was the third highest rank an adventurer could achieve, might be able to afford a mithril weapon. Only a person in the adamantite rank would be able to just give it away.
In the Anime, mithril is portrayed as a turquoise green metal.
- In the Web Novel, Aura Bella Fiora's shoes were plated with mithril. 
- Clementine’s stilettos and Climb’s armor were made of orichalcum alloyed over mithril.
- The White Dragon Bone, when wielded by the right mind, can possibly become harder than steel, maybe even rival mithril or even adamantite.
- Climb's mithril armor was actually created using leftover pieces given to him by Blue Roses.
- Succulent's sword was made of mithril.
- Marquis Blumrush's domain encompassed gold and mithril mines.
- In order to activate Heatstones, mithril at the barest minimum needed to be struck upon it.
- Some creatures such as the Gigant Basilisk and Quagoa had hides that could be as hard as mithril.
- The Azerlisia Mountains have large deposits of mitrhil deep within them which the dwarves of the Dwarven kingdom mine for.