Mortal Shell 2 provides players with two distinct methods to adjust the game's challenge: the Slayer Seal for a less demanding experience and the Gloombound Flame to activate Night Mode, which significantly increases difficulty.
The Slayer Seal, found in the Marrow Keep hub world, can be obtained from a glowing item located in an outer area accessible via a tunnel near the beacon. Equipping this item offers two primary benefits: Slayer Punch, a powerful charged attack that grants temporary invulnerability and deals significant break damage, potentially leading to an automatic riposte if an enemy's meter is full; and Gloomslayer, which enhances sidearm damage and restores health and resolve upon performing a riposte. However, a notable drawback to equipping the Slayer Seal is that it disables further achievement acquisition on the current save file. Players can carry the seal without equipping it to avoid this penalty.
To increase the game's challenge, players can acquire the Gloombound Flame from the Fainweald region. This item is located near a miniboss called the Great Arbiter of Flesh, close to the Widow's Overlook beacon. After obtaining the Gloombound Flame, players must return to the top of the Marrow Keep elevator and light a nearby brazier. This action summons Thestus, an NPC who offers the option to switch the game to Night Mode.
Night Mode drastically alters the game by not only darkening the environment but also by increasing enemy health, damage output, and sometimes their speed, thereby presenting a more formidable challenge. Conversely, enemies in Night Mode drop more gloom and health, which can be beneficial for players looking to farm resources for character progression. Additionally, certain areas may contain hidden secrets that are only visible during Night Mode, often indicated by riddles that hint at their nocturnal revelation. Players can revert to the standard difficulty settings at any time by returning to Thestus atop Marrow Keep and requesting the return of daylight.