Trail of the Master Sword

In-game Description

Obtained from Mineru at the end of the Spirit Temple.

Where even the sages of old could not defeat the Demon King, the darkness-sealing Master Sword wounded him.

According to Mineru, Princess Zelda said to speak to the Deku Tree about the Master Sword.

Head to Korok Forest by going through the Depths, ideally from the Minshi Woods Chasm. Near Rikonasum Lightroot, there’s a spot where you can Ascend up to the forest.

At the forest, you’ll find the Deku Tree has been gripped by the gloom. Head inside the tree and dive into the Deku Tree Chasm.

You will encounter a nasty Gloom Hand. The area is small and most of it is filled with gloom, making it tough to fight. If there’s enough distance between you, you can shoot Bomb Flowers using your bow to damage all the hands at once.

Once the Gloom Hand is gone, a Phantom Ganon will spawn. If you’re struggling, try to parry his attacks with your shield or evade them to trigger a Flurry Rush. You may want to eat some meals with an attack buff (eg. cooking Mighty Bananas together) before or during the fight to speed things up.