What to know
- The Mountain Temple Key is obtained through Naotora’s questline
- You must complete the Fated Land quest at Ryotan Temple first
- The key is given as a memento at Hamamatsu Castle Keep
- Using the key unlocks a Yokai-filled gate at Mountain Temple
Progression in Nioh 3 often depends on subtle quest handoffs rather than obvious key drops. The Mountain Temple Key is a good example of this design. Instead of being looted from an enemy or chest, it is tied to a short narrative chain involving Naotora, two separate locations, and a follow-up interaction many players miss.
If you’re standing in front of a locked gate at Mountain Temple and wondering what you skipped, this guide walks you through exactly how to get the key and how to use it correctly.
Nioh 3 Mountain Temple Key details
| Aspect | Details |
|---|---|
| Item name | Mountain Temple Key (Memento) |
| Quest required | Fated Land |
| First location | Ryotan Temple |
| NPC involved | Naotora |
| Second location | Hamamatsu Castle Keep |
| Usage location | Mountain Temple gate |
| Gate challenge | Yokai encounter |
Starting point: Ryotan Temple and the Fated Land quest
Your first step is traveling to Ryotan Temple and completing the Fated Land quest. This mission must be finished fully; partial completion or abandoning the quest will not advance the key’s progression.
After completing the quest objectives, remain in the area rather than leaving immediately. Naotora is present here, and speaking to them is mandatory. This conversation flags the next stage of the quest internally, even though the game does not explicitly tell you that a key reward is coming later.
At this point, you will not receive the Mountain Temple Key yet, which is where many players assume the chain is over.
Finding Naotora again at Hamamatsu Castle Keep
Once the Fated Land quest is cleared and you have spoken to Naotora at Ryotan Temple, move on to Hamamatsu Castle Keep. Naotora relocates here after the quest, and this second interaction is easy to miss if you don’t revisit the area.
Speak to Naotora again inside the keep. During this conversation, you are given a memento item, which functions as the Mountain Temple Key. The game does not rename it explicitly as a “key,” but it is this memento that unlocks the Mountain Temple gate.
Make sure the item appears in your inventory before proceeding.
What the Mountain Temple Key actually unlocks
The Mountain Temple Key is not used on a chest or door in a safe area. Instead, it opens a sealed gate at Mountain Temple that immediately leads into combat. This gate previously cannot be interacted with at all, even if you clear nearby enemies.
Once unlocked, the gate triggers a Yokai encounter, making this both a progression checkpoint and a combat challenge.
How to use the Mountain Temple Key
Step 1: Travel to Mountain Temple
Head to Mountain Temple and locate the sealed gate blocking the path forward. If you are at the correct location, the gate will now prompt an interaction.
Step 2: Use the Mountain Temple Key
Interact with the gate while the memento is in your inventory. The Mountain Temple Key is consumed automatically, and the gate opens without further input.
Step 3: Defeat the Yokai beyond the gate
Immediately beyond the gate, you will face multiple Yokai enemies. This is not a passive unlock—be prepared for combat. Clear the Yokai to fully secure the area and progress beyond the gate.
Why players commonly miss this key
The Mountain Temple Key is easy to overlook because it requires revisiting Naotora at a different location after an already-completed quest. There is no explicit quest marker pointing you to Hamamatsu Castle Keep, and the key being labeled as a memento rather than a traditional key adds to the confusion.
If you skipped the second conversation with Naotora, the Mountain Temple gate will remain locked indefinitely.
Nioh 3 quests and NPC involvement
The Mountain Temple Key is a small but important progression item that reinforces Nioh 3’s habit of tying exploration, NPC movement, and combat together. By completing the Fated Land quest, speaking to Naotora at both Ryotan Temple and Hamamatsu Castle Keep, and then challenging the Yokai behind the Mountain Temple gate, you unlock content that many players miss on their first run.
If the gate is locked, the solution isn’t grinding—it’s retracing your steps and finishing the conversation chain.
