Promotions Protocol Complete Guide
Tacit Brook to Maelstrom - Promotion Materials Farming Strategy
Last updated: 2026-02-09
Complete guide to Promotions Protocol Space in Arknights: Endfield with 5 stages (Tacit Brook to Maelstrom), SP generation mechanics, team compositions, and sanity-efficient farming for Basic and Intermediate Promotion Materials.
* TL;DR - Key Points
- * Best early promos: Stage 1-2 (Tacit Brook/Canal) - 40-50 Sanity for Basic materials
- * Best material density: Stage 4-5 (Undercurrent/Maelstrom) - 70-80 Sanity for Intermediate materials
- * Mechanic: Natural SP recovery very slow. Skill-based SP recovery greatly increased.
- * Location: The Hub - accessible mid-game (Authority Level 25+)
- * Total Sanity: 300 for all 5 stages
- * Primary rewards: Promotion materials (Basic/Intermediate)
Contents
What is Promotions Protocol Space?
Promotions Protocol Space is a combat challenge mode located in The Hub that rewards promotion materials for elevating operator tiers (E1, E2, etc.). It's the primary source of upgrade materials for operator advancement.
5 Stages
Tacit Brook to Maelstrom - 40-80 Sanity each
Basic Materials
8-34 Basic Promotion Materials per run
Intermediate Materials
8-14 Intermediate Materials (Set B, Stages 3-5)
Pro Tip: SP Mechanic
Natural SP recovery is very slow here. Build teams with multi-hit and combo-skill operators who generate SP actively through attacking and skill usage. Passive operators will struggle.
Complete Stage Overview
| Stage | Name | Sanity | Set A | Set B |
|---|---|---|---|---|
| 1 | Tacit Brook | 40 | 8 Basic Materials | N/A |
| 2 | Tacit Canal | 50 | 14 Basic Materials | N/A |
| 3 | Tacit Mere | 60 | 20 Basic Materials | 8 Intermediate |
| 4 | Tacit Undercurrent | 70 | 27 Basic Materials | 11 Intermediate |
| 5 | Tacit Maelstrom | 80 | 34 Basic Materials | 14 Intermediate |
Mechanics Breakdown - SP Recovery Altered
Mechanic: Natural SP recovery is much slower than normal. Skill-based SP recovery (from hitting enemies, combos, etc.) is greatly increased.
What This Means
- • Operators naturally gain SP very slowly over time
- • Using skills generates SP much faster than usual
- • Active playstyle required - cannot rely on passive SP generation
- • Need operators with good SP generation skills
How to Exploit
- • Build team with operators who have strong SP generation abilities
- • Prioritize skill usage and hitting enemies
- • Avoid passive operators who rely on natural SP recovery
- • Focus on high-attack-speed operators for consistent SP gain
Pro Tip: Best Operators
Multi-hit operators (more hits = more SP), Combo-skill focused operators (combo skills generate SP), Physical/Heat operators (typically attack speed focused), and operators with SP-generating passive abilities work best here.
Stage-by-Stage Walkthroughs
Stage 1: Tacit Brook (40 Sanity) - Easy
Unlocks immediately upon discovering protocol space
Basic enemies, 2-3 waves
Strategy: Build SP-generation team with multi-hit and combo-skill operators. Use skills as soon as available. Active playstyle required.
Pro Tip:
Excellent Sanity efficiency for Basic Promotion Materials. Run 2-3 times daily for E1 materials. Bring operators with strong SP generation.
Stage 2: Tacit Canal (50 Sanity) - Easy-Medium
Same enemies as Stage 1 with more HP
Strategy: Use Stage 1 team if clears are easy. Focus on SP generation. Active playstyle still essential.
When to Move: When Stage 1 clears are under 2 minutes and team generates SP consistently.
Stage 3: Tacit Mere (60 Sanity) - Medium
First stage with Set B option
Set A: 20 Basic Promotion Materials
Set B: 8 Intermediate Promotion Materials
Strategy: Maximize SP generation with multi-hit team. Choose Set B when progressing to E2.
Stage 4: Tacit Undercurrent (70 Sanity) - Hard
High HP enemies, 3-4 waves
Set A: 27 Basic, Set B: 11 Intermediate
Recommended: Operators Level 40+, E1 promoted team
Strategy: Build SP-heavy team with strong generation. Set B excellent for E2+ materials.
Stage 5: Tacit Maelstrom (80 Sanity) - Very Hard
Very high HP enemies, 4-5 waves
Set A: 34 Basic, Set B: 14 Intermediate
Recommended: Operators Level 60+, E2-E3 promoted team
Strategy: Maximize SP generation. Aggressive playstyle required. Only attempt when consistently clearing Stage 4.
Team Composition Guide
| Slot | Role | Recommended | Priority |
|---|---|---|---|
| 1 | Main DPS | Multi-hit Physical/Heat operators | High |
| 2 | Sub DPS | Combo-skill focused operator | High |
| 3 | Support | Healer or SP-buffer operator | Medium |
| 4 | Tank | High DEF/HP operator | Medium |
Pro Tip: SP Generation Focused
The slowed natural SP recovery demands an active playstyle. Build a team around operators who generate SP through attacking and using skills:
- • Multi-hit attackers (more hits = more SP)
- • Combo-skill specialists (combo abilities generate SP)
- • Physical/Heat operators (typically high attack speed)
- • Operators with SP-generating passives
When to Farm Promotions
| Authority Level | Recommended Stage | Runs Per Day |
|---|---|---|
| 25-30 | Stage 1-2 | 2-3 |
| 30-40 | Stage 2-3 | 2-2 |
| 40-50 | Stage 3-4 | 1-2 |
| 50+ | Stage 4-5 | 1-2 |
Common Mistakes & How to Avoid Them
1. Running Stage 5 too early
Problem: Attempting Tacit Maelstrom at Authority 25-30. Fix: Progress naturally. Stay on Stage 1-2 until operators Level 30-40. Stage 5 requires E2-E3 team.
2. Ignoring Set B options
Problem: Always choosing Set A when Set B might better suit your needs. Fix: Check your Promotion Material inventory. Choose Set B if you need Intermediate materials for E2+.
3. Not building for SP generation
Problem: Using passive operators when natural SP recovery is very slow. Fix: Prioritize multi-hit and combo-skill operators. Active playstyle required.
4. Being passive with SP
Problem: Playing like normal stages, not accounting for slowed natural SP recovery. Fix: Be aggressive! Attack constantly and use skills. Passive play won't work.
Quick Reference Checklist
Frequently Asked Questions
How many stages are in Promotions Protocol Space?
Promotions Protocol Space has 5 stages: Tacit Brook (40), Tacit Canal (50), Tacit Mere (60), Tacit Undercurrent (70), and Tacit Maelstrom (80) Sanity costs.
What rewards do Promotions Protocol stages provide?
Stages 1-2 drop Basic Promotion Materials. Stages 3-5 offer Set A (Basic) and Set B (Intermediate) Promotion Material options. Stage 5 Set B provides 14 Intermediate Promotion Materials.
What is the SP mechanic in Promotions Protocol?
Natural SP recovery is much slower than normal. Skill-based SP recovery (from hitting enemies, combos) is greatly increased, requiring an active playstyle with multi-hit and combo-skill operators.
When should I start farming Promotions Protocol?
Start around Authority Level 25+ with Stage 1-2 for E1 materials. Progress to Stage 3+ when operators reach Level 30-40 and are E1 promoted for Intermediate materials.
Which operators work best in Promotions Protocol?
Multi-hit Physical/Heat operators and combo-skill specialists excel because they generate SP the fastest. Avoid passive operators who rely on natural SP recovery.