Linnea, the 5-star Geo character introduced in Genshin Impact 6.5, is the first playable character with a fully customizable backpack. You can pin cosmetic badges to it — and even swap the companion eyes displayed on the pack — by working through a set of short investigation quests tied to a gadget called Linnea's Naturalist Archive. None of the tasks are difficult, but some are gated behind Friendship Levels, so you won't be able to finish everything on day one.
Quick answer: Pull Linnea, open Linnea's Naturalist Archive from your Gadgets tab, and complete all four investigation tasks plus the Special Lecture in each of the three categories (Plants, Ores, Animals) to earn every badge. Plants Investigation is available immediately; Ores Investigation unlocks at Friendship Level 3; Animals Investigation unlocks at Friendship Level 5.
Linnea's Naturalist Archive — Structure and Unlock Requirements
The moment you obtain Linnea from the Event Wish banner, a book called Linnea's Naturalist Archive appears in your Gadgets inventory. Opening it reveals three investigation categories, each containing four field tasks and one Special Lecture that caps off the category. Completing every task in a category rewards a badge you can pin to Linnea's backpack.
| Category | Tasks | Friendship Level Required | Badge Reward |
|---|---|---|---|
| Plants Investigation | 4 investigations + Flora Special Lecture | None (immediate) | Badge: Nocturnal |
| Ores Investigation | 4 investigations + Ores Special Lecture | Friendship Level 3 | Ores badge (name confirmed in-game) |
| Animals Investigation | 4 investigations + Animals Special Lecture | Friendship Level 5 | Animals badge (name confirmed in-game) |
Plants Investigation — Full Walkthrough
This is the only category available right away. It covers four plant-related field tasks spread across Nod-Krai, followed by a lecture in Nasha Town.
1. Winter Icelea Investigation
Step 1: Open Linnea's Naturalist Archive and accept "Plant Research: Winter Icelea." The quest marker points to the Wavechaser Plain area in Nod-Krai.
Step 2: Collect four Winter Icelea flowers from the marked zone. The quest completes as soon as you pick the fourth one.
2. Frostlamp Flower Investigation
Step 1: Accept "Plant Research: Frostlamp Flowers" from the Archive and travel to Hiisi Island in Nod-Krai.
Step 2: Gather four Frostlamp Flowers from the designated area to finish the task.
3. Twinleaf Pitcher Plant Investigation
Step 1: Accept "Plant Research: Twinleaf Pitcher Plants" and head to the Barrowmoss Barrens on Lempo Isle.
Step 2: Speak to the two Treasure Hunters near the quest marker. They'll ask you to find their missing cat.
Step 3: The cat is trapped inside the farthest Twinleaf Pitcher Plant in the swamp. Rescue it and return it to the Treasure Hunters to complete the quest.
4. Nocturnal Blossom Investigation
Step 1: Accept "Plant Research: Nocturnal Blossom" from the Archive. The location is also in Barrowmoss Barrens, close to the previous quest area.
Step 2: Collect two Nocturnal Blossoms from the marked zone. That's all it takes.
5. Flora Investigation Special Lecture
Step 1: After finishing all four plant investigations, return to Linnea's Naturalist Archive and tap "Unlock Special Lecture."
Step 2: Travel to Speranza in Nasha Town, Nod-Krai, to attend Linnea's lecture. She quizzes the local kids on the four plants you investigated.
Step 3: Answer the questions however you like — there is no penalty for wrong answers. Once the lecture ends, the quest completes, and you can claim Badge: Nocturnal from the Archive.
Ores Investigation and Animals Investigation
The Ores and Animals categories follow the same structure as Plants: four field investigations plus one Special Lecture. The key difference is the Friendship Level gate.
Reaching Friendship Level 3 with Linnea unlocks the four Ores Investigation quests. These send you to gather or interact with specific ore-related objectives across Nod-Krai, culminating in another lecture at Speranza. Friendship Level 5 does the same for Animals Investigation, which involves capturing creatures using Linnea's exploration passive and then presenting them to the kids in Nasha Town.
The fastest way to raise Friendship is to keep Linnea in your active party while completing Daily Commissions, spending Original Resin, and running through the Serenitea Pot companion system. Random Events in the open world also grant small amounts of Friendship EXP.
Backpack Companion Eyes
Beyond badges, Linnea's backpack has another customizable element: the companion eyes displayed on the pack itself. You can swap between at least three different eye styles through the Companions section of the customization menu. This option is separate from the badge system and does not require completing investigation quests — it appears to be available as soon as you have Linnea.
Where Linnea's Backpack Fits in Genshin's Customization Trend
Linnea's customizable backpack is part of a broader pattern in the 6.x update cycle. Varka received an exclusive weapon skin tied to a post-Story Quest challenge. Columbina gained the option to toggle her blindfold on or off after completing a specific Selenic Chronicle quest. Zibai has a unique teleport mechanic, and Durin unlocked an alternate skin. Linnea's badge system is the most granular version of this trend so far, giving players multiple cosmetic slots to mix and match rather than a single toggle.
Whether HoYoverse extends similar customization to older characters remains to be seen, but for now, Linnea's backpack is one of the more charming reasons to invest time — and Friendship EXP — into the Nod-Krai naturalist.