Deltarune Chapter 3 Guide - How I Found and Beat the Roaring Knight Secret Boss
After finishing Chapter 3 of Deltarune, I found out there's a secret boss fight that really puts your skills to the test — the Roaring Knight. It’s not something you can stumble into unprepared. You’ll need a special item called the Shadow Mantle to even stand a chance. I went through the whole process myself, and here’s exactly how I did it.
🔍 How To Find the Roaring Knight
You’ll actually run into the Roaring Knight automatically at the end of Chapter 3, right after the Teena boss fight. But don’t rush in! This fight is brutal — the Roaring Knight can wipe your entire team in just a few turns if you're not ready.
Tip: Save your game right after beating Teena. You’ll need to go get the Shadow Mantle first before coming back.
🧥 How I Got the Shadow Mantle
✅ Step 1: S Rank the First Board
First, I had to earn an S Rank on the first Board. It took a few tries, but I got there by:
- Grinding up to 1,500 points (T Rank helps)
- Grabbing all four keys
- Focusing on the cooking mini-game
✅ Step 2: Unlock the S Rank Room
After getting S Rank, I entered the S Rank-only room in the Green Room. On the left side, there’s an NPC who let me into the backstage. That’s where the next phase began.
✅ Step 3: Complete the Backstage Mini-Game
In backstage, I played a mini-game where I had to:
- Find a sword
- Farm EXP by defeating enemies
- Reach level 3 to cut down cacti
- Level up more to chop down trees
Eventually, I made my way into a forest where I found the Ice Key — this was super important later.
🟩 Step 4: S Rank the Second Board
With the Ice Key in hand, I exited the mini-game and moved on to the second Board.
To get an S Rank here, I had to:
- Collect all four photos
- Play the concert mini-game
- Eat moss (yes, really)
Then I went back to the Green Room again.
🎮 Step 5: Play the Console Mini-Game
Back in the S Rank room, another mini-game unlocked:
- I leveled up again by beating more enemies
- Eventually, I found a raft and sailed into icy waters
- After landing, I entered a temple and fought through waves of enemies
- This is where I got the White Cloak, which gave me ice attacks
🗝️ Step 6: Use the Ice Key and Find the Shelter Key
I reached a locked door, used the Ice Key, and entered a dark room. There, I picked up a shiny item — the Shelter Key.
🛡️ Step 7: Fight the Shadow Mantle Boss
With the Shelter Key, I unlocked the final mini-game in the S Rank area. Susie, Kris, and Ralsei joined me this time.
I followed the story until I met Toriel, who led us into the Shelter. Inside, I faced the Shadow Mantle mini-boss. The fight was tough, but dodging carefully and attacking when safe got me through.
Reward: The Shadow Mantle, which is essential for surviving the Roaring Knight.
⚔️ How I Beat the Roaring Knight
Once I had the Shadow Mantle, I equipped it to Susie and loaded my save from right after the Teena fight.
Here’s what I learned from the battle:
🌀 Roaring Knight’s Main Attacks
Here are the five main attacks you’ll need to watch out for during the fight:
-
Ice Crystal Barrage
Low damage with small hitboxes. One of the easier attacks to dodge. -
Gaster Sword Blasters
Extremely dangerous — usually a one-hit KO. You’ll need lightning-fast reflexes to survive. -
Lemonbread Slash
A heavy-hitting, fast attack. Very difficult to avoid. -
Swords’ Dance
Nearly impossible to dodge. Prepare to take damage and heal quickly. -
Slash
Low damage and the easiest of his attacks to dodge. Use this time to recover or counter.
You only need to take down 25% of his HP to win.
🛠️ Best Gear Setup I Used
🛡️ Recommended Equipment Setup
Here’s what worked best for my team when facing the Roaring Knight:
-
Susie
- Shadow Mantle
- Jevilstail
- Toxic Axe
-
Kris
- Saber10
- Spikeband
- Twin Ribbon
-
Ralsei
- Dealmaker
- Twin Ribbon
- Flex Scarf
Susie is your tank here — with the Shadow Mantle, she’s your MVP.
🎁 Rewards for Winning
Beating the Roaring Knight earned me:
- A Black Shard (for Kris — really strong against dark enemies)
- A Shadow Crystal (after Susie knocks a piece off his blade)
These items will definitely come in handy in future chapters.
Final Thoughts
The Roaring Knight is no joke, but with the right prep — and the Shadow Mantle — it’s doable. The whole journey to get the armor is like a game within a game, and I loved the challenge. If you’re aiming to 100% Chapter 3, don’t skip this fight.
Good luck out there!