If you’ve just cleared the opening of Duet Night Abyss and claimed your first free unit, the next big decision is simple: who should be your second character, and how do you unlock them without wasting time? With all characters available for free and progression centered on repeatable missions, a little planning goes a long way.

How unlocking works (Secret Letters, Covert Commissions, Thoughts)

Characters, weapons, and Demon Wedges are tied to the Secret Letter system. You exchange 10 Secret Letter Clues for a Secret Letter, run a level-40 Covert Commission, and then select one reward from a small post-mission loot pool. Character Thoughts can appear in that pool; you need 30 Thoughts to unlock a character.

  • Covert Commissions rotate objectives hourly by category (Character, Weapon, Demon Wedge) but keep reward pools consistent.
  • Gold-tier drops like 10 Thoughts are rare; expect a grind to hit 30 Thoughts for a single unlock.
  • Most characters are also tied to story progression or events, but Secret Letters are still required for Intron upgrades later.
Tip: Covert Commissions are set at level 40. If they’re punishing early on, progress further in the main story to gear up before you farm.

Where to farm Secret Letter Clues (weekly and daily sources)

  • Main story and major side quests: early, one-time infusions of Secret Letter Clues.
  • Daily objectives: steady flow; completing your dailies grants 15 Secret Letter Clues.
  • Mystic Maze: 30 Secret Letter Clues weekly.
  • Immersive Theater: up to 280 Secret Letter Clues per refresh, plus featured Secret Letters for the newest character during their opening window.
  • Nocturnal Echoes (weekly bosses): Secret Letters for the latest characters rotate through this pool.
Note: Once early freebies and pre-registration rewards are spent, these repeating activities become your long-term source of Secret Letters.

Free characters and easy early unlocks you shouldn’t miss

  • Margie (Pyro): granted after the tutorial and comes with a Vernal Jade Halberd. An immediate second playable option if you rushed straight through the opening.
  • Truffle and Filbert (Anemo, Support): available by completing “Go, Geniemons!” and the “Tutorial: Covert Commissions” quests. A fast path to a high-impact support unit.
  • Lisbell (Lumino, DPS): unlocked by finishing the chapter “Noctoyager [On a Gentle Breeze].” Strong damage dealer you can earn via story.
  • Berenica (Umbro, DPS): handed out via the pre-registration event if you met the requirements during the launch window.

These picks expand your roster quickly without deep Secret Letter investment, letting you spend your early Clues where they matter most.

New character window (why timing matters)

Brand-new characters follow a fixed availability arc:

  • First 28 days: their Secret Letters are featured in Immersive Theater.
  • After 28 days: they shift into the Nocturnal Echoes weekly boss rewards.
  • Later: their Secret Letters become available for Secret Letter Clues in the shop.

At launch, Psyche is the Immersive Theater feature. Nocturnal Echoes bosses during the early window reward Secret Letters for Tabethe, Truffle and Filbert, Yale, and Rhythm. If you can consistently clear Immersive Theater at high ratings, targeting the featured character right away is efficient; otherwise, you can wait until they move into weekly boss rewards or the shop.

Who to unlock second: strong early targets by role

Your second character should complement your starter. If you lead with a DPS, grab a support that stabilizes the team; if you began with a free support, target a high-uptime damage dealer. The options below are consistently strong at launch and have clear paths to acquisition.

Role Character Why target second How to get now
Support Truffle and Filbert (Anemo) Top-tier sustain and team utility for bosses and farming; easy early access. Complete “Go, Geniemons!” and “Tutorial: Covert Commissions.”
Support Daphne (Anemo) Control and healing support that stabilizes fragile DPS teams. Secret Letters; farm Thoughts via Character Covert Commissions.
DPS Rebecca (Hydro) Area damage and summon pressure for objective defense and mobbing. Secret Letters; prioritize Character Commissions for Thoughts.
DPS Lisbell (Lumino) High burst with strong uptime once unlocked through story. Finish “Noctoyager [On a Gentle Breeze].”
DPS Yale and Oliver (Pyro) Safe damage from aerial bombing; good flexibility. Nocturnal Echoes weekly bosses (launch window) and Secret Letters.
DPS Psyche (Anemo) Featured early; efficient to target if you can clear Immersive Theater. Immersive Theater featured Secret Letters, then Nocturnal Echoes later.
DPS Berenica (Umbro) Reliable DPS with strong weapon synergy. Free via pre-registration event (if claimed); otherwise Secret Letters.
Tip: If you’re crafting a two-character core for early content, pairing a reliable DPS (Rebecca, Lisbell, Psyche) with a proven support (Truffle and Filbert, Daphne) covers most mission types.

Secret Letter odds and expectations

After each successful Covert Commission, you choose one reward from three items drawn from the letter’s pool. High-value drops are rare; for example, a 10-Thought reward sits at a low drop rate, so plan for multiple runs. If you’re chasing a weapon or Demon Wedge instead, you only need a blueprint to unlock the forging option, with materials dropping from the same Secret Letter source.

Note: You can purchase individual Thoughts with premium currency (150 Phoxene Plumule each) through the in-game shop if you want to shortcut a specific unlock.

Roster size at launch

There are 18 playable characters at launch, including the customizable player character (Phoxhunter). The rest split across elements like Hydro, Pyro, Anemo, Electro, Lumino, and Umbro, with multiple roles (DPS, Support) and weapon proficiencies.

When to target weapons instead of a second character

If you already have a functional DPS and support pair, consider spending early Secret Letters to snag a signature weapon blueprint for your main carry. Unlocking a weapon can be a one-and-done drop; the ongoing grind is crafting materials, which come from the same letter pool. This approach can be more efficient than splitting your Thoughts across multiple characters too early.

Install the game and start the climb

If you haven’t installed the game yet, grab the PC version from the Epic Games Store and link your account before you begin farming daily and weekly sources for Secret Letter Clues.

Download Duet Night Abyss on Epic Games Store

The quickest route to a great second character is to bank your early story unlocks, finish the two short quests that grant Truffle and Filbert if you need support, and then funnel Secret Letters into a single, targeted DPS or featured unit. With a daily routine for Clues and a weekly pass through Mystic Maze, Immersive Theater, and Nocturnal Echoes, you’ll reach 30 Thoughts on your pick without spending a cent.