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Mortal Shell II Open Beta Walkthrough: Prologue, Tiel, Beacons and Marrow Keep

A source-backed Mortal Shell II Open Beta walkthrough covering the Prologue, first region, Tiel, beacons, optional dungeons, mini-bosses, Magdalena and Marrow Keep.

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This Mortal Shell II Open Beta walkthrough is a route and completion checklist for the public Beta build. It follows the sequence that Steam actually confirms instead of pretending the limited Beta is the full game.

What the Open Beta includes

The official Steam page says the Beta covers the opening hours of Mortal Shell II: the Prologue and the first explorable region. The route includes Shell possession, beacon cleansing, optional dungeons, hidden mini-bosses and challenges, then an onward objective involving Magdalena, the Lady of the Woods.

Steam’s short description calls the Beta roughly three hours of content, but completion time depends on whether you explore optional areas, repeat fights or pursue the available achievements.

1. Finish the Prologue before chasing optional content

Use the opening section to learn the Beta’s movement, dodge, hardening/parry timing and critical-strike rhythm. Do not treat the first run as a speedrun: the Beta is deliberately structured to introduce the combat loop before opening the wider route.

2. Enter the first explorable region

Once the Prologue opens into the early region, make a first pass along the main route. Mark blocked paths and unfamiliar landmarks mentally rather than assuming every sealed route is available in the Beta. The store page only promises the early section, not the complete world map.

3. Find and claim Tiel

The Open Beta officially includes Tiel, the Acolyte, one of the eight Shells announced for the full game. Seek his remains, possess the Shell and awaken its innate abilities. The Steam achievement list also includes Claim Tiel, making this a clear Beta completion target.

4. Cleanse beacons before leaving an area

Beacons are part of the confirmed Beta loop. Cleanse the ones you encounter before pushing onward, especially if you are working toward the Steam achievement Cleanse all Beacons. This is also a useful way to turn exploration into a checklist instead of repeatedly retracing the same route.

5. Check optional dungeons and hidden challenges

The official Beta description specifically calls out optional dungeons, hidden mini-bosses and challenges. They are not required simply to see the opening route, but they are the most important detours for players who want to understand the combat, discover additional equipment and complete more of the Beta.

6. Continue toward Magdalena

After exploring the early region and its optional content, follow the main objective toward Magdalena, the Lady of the Woods. The official Steam text names her as the onward destination, but it does not publish a complete boss guide or a full encounter table for the Beta.

7. Reach Marrow Keep if you want the carry-over option

The Steam Beta page states that progressing beyond Marrow Keep unlocks the option to skip the Prologue in the full game. This is a launch convenience, not a full-save transfer.

Open Beta completion checklist

  • Finish the Prologue.
  • Enter the first explorable region.
  • Find and claim Tiel.
  • Cleanse every beacon you can locate.
  • Explore optional dungeons.
  • Test the hidden mini-bosses and challenges.
  • Find the Axe and Dagger objective listed by Steam achievements.
  • Complete the Beta route toward Magdalena.
  • Reach Marrow Keep for the Prologue-skip option in the full game.

What carried into the full release?

The Beta did not transfer currency, weapons, Shells, collectibles or other normal items. The official carry-over was limited to the Flayed Harbinger cosmetic reward and the Prologue-skip option after reaching Marrow Keep.

Scope note

This is an Open Beta route, not a retail walkthrough. Exact full-game chapters, final boss order, complete Shell locations and the definitive weapon list should be added only after the retail build is verified on or after August 20, 2026.