What does Fiend do as a monsterling?

Equipped on a character, Fiend triggers a link skill: "Using a Switch Skill". The skill activates each time the condition is met during combat.

Tame Fiend in the open world to recruit Fiend. The bestiary entry above lists every spawn location.

Fiend cannot be merged with another monsterling. Keep it on its current character for the link skill.

What are Fiend's reinforcement costs?

Fiend reinforces up to level 60. Total cost: 5,025,139 EXP and 25,125,695 gold.

How many variants does Fiend have?

Fiend ships in 5 rarity variants — base ATK/DEF/HP scales from the lowest to the highest tier. The Variants section above lists each one.

Mongil Codex · Monsterling · #120

Fiend

Element Fire

Fire
Grade 2

Fiend is a rare boss-type Fire-element Monsterling. It stands 68.0–80.0 m tall and weighs 380–450 kg. Available in 5 variants: N (1★), N (2★), R (3★), SR (4★), SSR (5★). Base stats range from 23/36/111 ATK/DEF/HP at N to 45/70/222 at SSR. Ability: Fire DMG +11.6% upon attacking with a Fire Special Skill Obtainable through fusion: Duoxini + Ashen Mask (20%).

Last updated May 2026 · Verified for the latest Mongil: Star Dive build

Last reviewed by Trakan — May 13, 2026

Profile

Height: 68.0–80.0 m
Weight: 380.0–450.0 kg
Companion scale: 0.50×Display size

Link skill

Link skill · Lv. 5 · Fire

Using a Switch Skill

If the Fiend Monsterling is equipped, it appears when its Appearance Condition is met. It throws a totem at the ground, dealing Fire DMG, then gets on top of the totem, inflicting Bonus Effects within range and rendering the enemy Airborne.

[Appearance Condition]
Using a Switch Skill
Using an Ultimate Skill

[Appearance Info]
DMG based on equipping character's ATK: 200%
Cooldown: 8s

[Bonus Effects]
Totem Duration (10s)
Grants Character Super Armor
15% Elemental Weakness DMG Boost

Damage: 200% · Cooldown: 8s

Chain-link unlocked at level 25.

Stats

Per-level ATK/DEF/HP scaling — and the reinforcement cost to reach each level. Switch rarities to see how the same level lands at higher floors; scrub the slider to see the cumulative EXP, gold, and best-fit feed mix update live.

LevelLv. 60/ 60

HP2,721+2,499 from Lv. 1
ATK818+773 from Lv. 1
DEF1,275+1,205 from Lv. 1

Reinforcement to Lv. 60

Target level: 60Lv.
Cumulative EXP: 3,768,879EXP
Cumulative gold: 25,125,695Gold

Recommended feed mix to reach Lv. 60

Variants

Fiend ships in 5 rarity variants. Each variant scales the same base ATK/DEF/HP curve at different floor values. Use the stats section to scrub the per-level curve for any rarity.

N★23/36/111
N★★26/39/123
R★★★31/46/145
SR★★★★37/57/178
SSR★★★★★45/70/222

Tame from bestiary

Origin monsterFiendOpen bestiary entry →

Comments

Guides

In-house guides re-tested every patch.

Guides and articles content remains in English.

Mongil: Star Dive — Beginner Guide

Adventure map, jumping, gathering and the first-week checklist — every core mechanic the in-game tutorial walks you through, written in one place.

Trakan

Updated Patch 1.0

Reroll Guide — Best Targets and Stop Conditions

Best characters to chase on a fresh account, the fastest reroll path, and when the meta says you should stop and commit.

Trakan

Updated Patch 1.0

Best Team Comps — Destroyer, Slayer and Flex Slot

How team building actually works in Mongil — the Destroyer + Slayer + flex template the Stagger system rewards, when to break it for element-locked counters, and the Brawler-led sustained-DPS variant.

Trakan

Updated Patch 1.0

Combat Basics — Hold Attacks, Switch Skills, Ultimates

Basic attacks, special skills, switch skills and ultimate timing — the hold-input combat system explained without the in-game popup spam.

Trakan

Updated Patch 1.0

Frequently asked

What does Fiend do as a monsterling?: Equipped on a character, Fiend triggers a link skill: "Using a Switch Skill". The skill activates each time the condition is met during combat.
How do I get Fiend?: Tame Fiend in the open world to recruit Fiend. The bestiary entry above lists every spawn location.
Can I fuse Fiend?: Fiend cannot be merged with another monsterling. Keep it on its current character for the link skill.
What are Fiend's reinforcement costs?: Fiend reinforces up to level 60. Total cost: 5,025,139 EXP and 25,125,695 gold.
How many variants does Fiend have?: Fiend ships in 5 rarity variants — base ATK/DEF/HP scales from the lowest to the highest tier. The Variants section above lists each one.