# Operator EXP Protocol 2026 - Walkthrough

> Arknights Endfield Operator EXP Protocol Space guide. Stage walkthroughs, team comps, combo mechanics, and Sanity-efficient leveling.

Source: https://endfieldhub.org/guides/operator-exp-protocol
Published: 2026-02-09
Updated: 2026-02-09

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.