Here's a detailed guide on Calm Before the Storm, which is indeed part of the Archon Quest in Genshin Impact. Remember, this guide reflects the general gameplay as of this writing. If there have been recent changes or updates to Genshin Impact specifics like rewards or exact quest mechanics might differ.
Unlocking 
1.Prerequisites: Complete the previous parts of the Archon Quest "Prologue: Act III - Song of the Dragon and Freedom." This means you should have already completed the quests leading up to this, including encounters with the dragon, Dvalin, and interactions in Mondstadt.
2.Adventure Rank: Typically, you would need to be around AR 18 or higher to ensure you've progressed enough in the story and have the necessary experience with the game's mechanics.
Walkthrough
1.Meeting at the Favonius Cathedral: Begin by speaking with Jean at the Knights of Favonius headquarters or directly at the Cathedral in Mondstadt. This conversation sets the stage for impending conflicts with Stormterror (Dvalin).
2.Gathering Information: You might need to talk to various NPCs around Mondstadt to gather information or resources for the upcoming battle. This could include characters like Venti, Diluc, or even Kaeya.
3.Preparation for Battle: There might be a segment where you prepare defenses or enchantments. This could involve:
4.Collecting materials for Venti to enhance his abilities or for crafting items that will help in the fight against Dvalin.
5.Meeting at Stormterror's Lair: Travel to Stormterror's Lair, which might involve a sequence where you, Venti, Jean, and perhaps Diluc plan your approach.
6.Confronting Stormterror: First Encounter: You'll likely have an initial skirmish or a chase sequence with Dvalin, where you try to calm him down or fend off his attacks without causing him harm.
7.Purification: Use Venti's abilities or other mechanisms to purify or weaken Dvalin's corruption. This part might involve gameplay mechanics like dodging attacks, flying, or puzzle elements to reach Dvalin.
8.Resolution and Planning: After an initial confrontation, there might be a temporary retreat or a moment where you learn more about Dvalin's plight, setting up for the next phase of the quest.
9.Ending the Quest: Return to Mondstadt for a debrief with the Knights or Venti. Here, you discuss the next steps or reflect on what you've learned about the Abyss Order's involvement.
Rewards
•Primogems: For completing this significant part of the storyline.
•Adventure Experience: Substantial amount for quest completion.
•Mora: To aid in your in-game economy.
•Character Experience Materials: Useful for leveling up your characters involved in the quest.
•Story Progression: Unlocking new dialogues, character insights, and potentially new quests or areas.
Quest Tips 
•Elemental Synergy: Ensure your party has good elemental diversity to handle Dvalin's different phases if there are combat elements involved.
•Healing Items: Stock up on food for healing and buffs to help during the confrontation with Dvalin.
•Character Levels: Make sure your characters are leveled appropriately for the battle, as Dvalin can be a tough opponent, especially in corrupted form.
•Venti's Utility: If Venti is part of your strategy, his ability to create wind currents can be very useful for navigation during the quest.
Remember, the specifics of quests can change with game updates, so if there have been updates or changes to this quest since my last knowledge update, you might want to check the in-game quest log or recent player guides for the most accurate information.
