The Mighty Lynel Sword is an item from The Legend of Zelda: Breath of the Wild. It is a sword wielded by Blue-Maned and White-Maned Lynels which Link can obtain by defeating them. It is the second strongest of the three Lynel-made swords.
As all blue-maned lynels (execpt the one in the First Gatehouse) are eventually replaced with white and silver maned lynels, all mighty lynel gear including the mighty lynel sword eventually become unobtainable. However via a glitch, Link can acquire the First Gatehouse's Blue-Maned Lynel's sword if he quickly presses the "Take" command as the Lynel dies and drops it spoils as the sword is normal programmed to drop when it is killed but the Gatehouse Lynel's equipment disappears however since it is dropped momentarily for a brief instant, Link can grab it before it disappears. If Link hasn't obtained said gear, then the test box pause will cause the Lynel's remaining equipment to not disappear.