Strategy & Tips
The Roaring Knight is easily the hardest fight in Deltarune as a whole. Designed to be a scripted loss, their attack patterns are extremely quick and difficult to react to, and each hit will do devastating damage. Under normal circumstances, most attempts against the Roaring Knight will end after a few turns, which is by design and a perfectly legitimate strategy if you are unconcerned with acquiring the Roaring Knight's unique drops. However, for those who never back down from a challenge there is a vital piece of equipment which can make what is normally an insurmountable foe into an incredibly difficult, yet surmountable challenge. The Shadow Mantle is a piece of armor that when equipped reduces the damage of the Roaring Knight's attacks against the wielder by 66%. They'll still be hitting incredibly hard, but now the character with the mantle equipped will be able to survive more than one hit. Ideally, Susie should be equipped with the mantle, as she has the highest potential damage output and her higher total HP will ensure she makes full use of the item's defensive potential.
As for the fight itself, the Roaring Knight is actually fairly predictable, repeating a cycle of attacks that have very little randomness involved. This makes learning the fight fairly simple once the Shadow Mantle prevents you from being punished with an instant loss for even the tiniest mistake. The Roaring Knight's attacks tend to test your reflexes, giving you tiny windows to react and rewarding precise, deliberate movement. There is a noticeable exception to this rule in the form of the Blade Hallway attack, which sends a constant flurry of projectiles at you that you must avoid by carefully snaking through them. These projectiles all come in from the right and move to the left, so positioning yourself to the far left of the battle box and focusing on the projectiles coming in from the right is a helpful strategy as it maximizes the amount of time you have to adjust your position and react in time. It's important to remember that at the very end of this attack all of the projectiles currently on screen will freeze in place before aiming at the player, their location locks before firing so it is important to move out of the way shortly after the lock on in order to avoid taking lethal damage. After you've defeated this impressive test of endurance, you will be rewarded more than fairly, acquiring a Shadow Crystal (one of five needed for Seam's quest) and a unique weapon known as the Black Shard, a weapon exclusive to Kris that provides an impressive +16 attack boost while also nearly tripling damage to Dark-Type enemies, which is incredibly useful for the final boss of Chapter 4, the Titan.