Operator EXP Protocol Complete Guide
Derivative Memories to Nightmares - EXP Crystals and Combat Records Farming
Last updated: 2026-02-09
Complete guide to Operator EXP Protocol Space in Arknights: Endfield with 5 stages (Derivative Memories to Manifested Nightmares), combo skill mechanics, enemy HP regeneration, team compositions, and sanity-efficient Combat Records and EXP Crystals farming.
* TL;DR - Key Points
- * Best early EXP: Stage 1-2 (Derivative Memories/Trials) - 40-50 Sanity for Basic Combat Records
- * Best material density: Stage 4-5 (Destruction/Nightmares) - 70-80 Sanity for Intermediate Combat Records
- * Mechanic: Lv 2+ reduces combo skill CD + ATK buff. Lv 3+ enemies slow HP regen
- * Location: Valley Pass - accessible early (Authority Level 20+)
- * Total Sanity: 300 for all 5 stages
- * Primary rewards: Combat Records, EXP Crystals, Skill Books
Contents
What is Operator EXP Protocol Space?
Operator EXP Protocol Space is a combat challenge mode located in Valley Pass that rewards Combat Records, EXP Crystals, and Skill Books for leveling up operators. It's the primary operator leveling resource in the game.
5 Stages
Derivative Memories to Nightmares - 40-80 Sanity each
Basic Materials
EXP Crystals, Basic Combat Records, Basic Skill Books
Intermediate Materials
High-tier Combat Records and Skill Books (Stages 3-5)
Pro Tip: Combo Skill Synergy
The Lv 2+ combo skill synergist (reduced CD + ATK buff) rewards aggressive play. Build a team around operators with strong combo skills, chaining them together for sustained buffs and shorter cooldowns.
Level 1-2 Mechanic: Combo Skill Synergy
Mechanic: Operators enjoy shorter combo skill cooldown and gain temporary ATK buff after casting their combo skills.
What This Means
- • Combo skills have reduced cooldown
- • After using combo skill, operator gets temporary ATK boost
- • Rewards aggressive playstyle that uses combo skills frequently
How to Exploit
- • Build team with operators who have strong combo skills
- • Prioritize combo skill usage over basic attacks
- • Maintain attack chains to activate combo skills
- • Chain combo skills for sustained ATK buff
Level 3+ Mechanic: Enemy HP Regeneration
Mechanic: Enemies have slow HP regeneration that must be outdamaged.
Critical: High DPS Required
Enemies in Stage 3+ slowly heal over time. If damage output is too low, enemies regen faster than you damage. Requires sustained high DPS to overcome regen. Build dual-DPS teams and consider DoT effects.
Stage-by-Stage Walkthroughs
Stage 1: Derivative Memories (40 Sanity) - Easy
Rewards: 4 EXP Crystals, 3 Basic Skill Books, 2 Basic Combat Records
Basic enemies, 2-3 waves. Low HP.
Strategy: Balanced team 2 DPS + 1 Support + 1 Tank. Focus on combo skills. Excellent Sanity efficiency.
Stage 2: Derivative Trials (50 Sanity) - Easy-Medium
Rewards: 6 EXP Crystals, 9 Basic Skill Books, 4 Basic Combat Records
When to Move: When Stage 1 clears are fast and easy (under 2 minutes).
Stage 3: Derivative Suffering (60 Sanity) - Medium
Set A: 9 EXP Crystals, 9 Basic Skill Books, 4 Basic Records | Set B: 4 Intermediate Combat Records
Mechanic: Enemies slow HP regeneration. Requires high DPS.
Strategy: Increase DPS to overcome HP regen. Choose Set B if needing Intermediate Combat Records.
Stage 4: Derivative Destruction (70 Sanity) - Hard
Set A: 13 EXP Crystals, 7 Intermediate Skill Books, 2 Intermediate Records | Set B: 5 Intermediate Combat Records
Recommended: Operators Level 40+, E1 promoted
Stage 5: Manifested Nightmares (80 Sanity) - Very Hard
Rewards: 17 EXP Crystals, 6 Intermediate Skill Books, 8 Intermediate Combat Records
Recommended: Operators Level 60+, E2-E3 promoted
Strategy: Endgame content. Maximize DPS to overcome strong HP regen. Highest Combat Record density.
Team Composition Guide
| Slot | Role | Recommended |
|---|---|---|
| 1 | Main DPS | Physical/Heat operators with strong combo skills |
| 2 | Sub DPS | Complementary element operator |
| 3 | Support | Healer or buffer operator |
| 4 | Tank | High DEF/HP operator |
When to Farm Operator EXP
| Authority Level | Recommended Stage | Runs Per Day |
|---|---|---|
| 20-25 | Stage 1-2 | 2-3 |
| 25-30 | Stage 2-3 | 2-2 |
| 30-40 | Stage 3-4 | 1-2 |
| 40-50 | Stage 4-5 | 1-2 |
Common Mistakes & How to Avoid Them
1. Running Stage 5 too early
Problem: Attempting Derivative Nightmares at Authority 20-25. Fix: Progress naturally. Stay on Stage 1-2 until operators Level 30-40. Stage 5 requires E2-E3 team.
2. Not building for combo skills
Problem: Using basic-attack operators when Lv 2+ reduces combo skill cooldown. Fix: Prioritize operators with strong combo skills. Chain combo skills for ATK buffs.
3. Ignoring HP regen mechanic (Stage 3+)
Problem: Playing Stage 3-5 like Stage 1-2, not accounting for enemy healing. Fix: Build high-DPS team. Enemies in Stage 3+ slowly heal - you must outdamage them.
Quick Reference Checklist
Frequently Asked Questions
How many stages are in Operator EXP Protocol Space?
Operator EXP Protocol Space has 5 stages: Derivative Memories (40), Derivative Trials (50), Derivative Suffering (60), Derivative Destruction (70), and Manifested Nightmares (80) Sanity costs.
What rewards do Operator EXP Protocol stages provide?
Stages drop EXP Crystals, Basic/Intermediate Skill Books, and Basic/Intermediate Combat Records. Stages 3-5 offer Set B option for Intermediate Combat Records instead of Basic ones.
What is the combo skill mechanic in Operator EXP Protocol?
Level 2+: Operators enjoy shorter combo skill cooldown and gain temporary ATK buff after casting combo skills. Level 3+: Enemies have slow HP regeneration requiring high DPS to overcome.
When should I start farming Operator EXP Protocol?
Start around Authority Level 20+ with Stage 1-2 for Basic Combat Records. Progress to Stage 3+ when operators reach Level 30-40 and you can overcome HP regen.
Which operators work best in Operator EXP Protocol?
Operators with strong combo skills, Physical finishers, Heat burst operators, and chain-combo specialists excel due to Lv 2+ combo skill cooldown reduction and ATK buffs.