Hell's Park Underside
Boss Guides[edit]
Hell's Park Underside is a mode where you fight bosses that have customizable difficulty levels. It is unlocked after clearing all 100 "surface" stages of Hell's Park.
Overview[edit]
Hell's Park Underside re-uses the area names of the original Hell's Park, but it has only 1 boss fight (consisting of 4 enemies) per area. Each boss can have their difficulty level customized, starting at level 1 and going up to an unknown maximum.
Each area is weak to a specific element, and has 3 possible rulesets for which kinds of demons you can bring in. 3 areas are available each month, and the available ruleset for each area also changes each month.
Clearing a stage for the first time grants gold and silver Friendship Badges, which can be exchanged for rewards. These first-clear rewards are reset every month.
Rules[edit]
All battles in Hell's Park Underside have a general set of restrictions in place:
- You cannot pierce attributes (for example, Fire Pierce effects will not work). Enemies can still pierce, though!
Attribute affinity down does not work.- Anti-pierce effects do not work.
- Press Turn Generation and Press Turn Removal do not work.
- Press Turn Retention (such as Chief God's Rage or Tag) do not work.
- Remnants and Critical Hits will not use half a Press Turn, unless they also hit a weakness.
- Damage reduction and reverse damage reduction do not work.
- Dx2 Skills (from Liberators) do not work.
Additionally, each area will impose their own restrictions on the demons you can bring, depending on the difficulty level selected.
However, you are allowed to use items for reviving, healing, etc!
You are also allowed to use your Devil Connector.
Enemies are not subject to these restrictions, with one exception: an enemy landing a Critical Hit will not use half a Press Turn, unless they also hit a weakness.
Difficulty levels[edit]
Before challenging a stage, its difficulty level can be selected. Higher difficulties will increase enemy stats, add skills to the enemy, and add team-building restrictions.
- Enemies start with 3 skills. They gain their 4th at level 3, their 5th at level 6, and their 6th at level 9.
- After level 9, the only thing that changes is stats.
When a stage is cleared, the player receives the reward for that level, as well as the rewards for all levels below it. These rewards reset monthly.
Initially, only 10 difficulty levels are available for each stage. Clearing level 10 on a stage unlocks levels 11-20 for that stage, clearing level 20 unlocks levels 21-30, and so on.
- The maximum possible level isn't currently known, but rewards stop being given from level 501 onwards.
| Level |  Gold |
 Silver
|
|---|---|---|
| 1 | 50 | 50 |
| 2 | 50 | 50 |
| 3 | 50 | 200 |
| 4 | 20 | 200 |
| 5 | 20 | 200 |
| 6 | 10 | 300 |
| 7 | 10 | 300 |
| 8 | 10 | 300 |
| 9 | 5 | 400 |
| 10 | 5 | 400 |
After the first 10 levels, each level no longer gives gold badges. Instead, each level gives a standardized amount of silver badges, depending on the level range.
- Levels 501 onwards do not give any rewards.
| Level | Silver per level
|
|---|---|
| 11-20 | 300 |
| 21-100 | 50 |
| 101-500 | 10 |
Score and ranking[edit]
When you clear a battle in Hell's Park Underside, you'll earn a score based on your performance. Score is awarded based on several factors:
- The level of the battle cleared (the higher, the better).
- Clearing the battle in a small amount of turns.
- Having unused Press Turns remaining.
- Dealing a lot of total damage.
Your score will be assigned a letter rank, based on how high it is:
| Rank | score |
|---|---|
| SSS | 1,200,000+ |
| SS | 600,000-1,199,999 |
| S | 300,000-599,999 |
| A | 125,000-299,999 |
| B | 68,500-124,999 |
| C | 38,500-68,499 |
| D | 26,500-38,499 |
| E | 17,500-26,499 |
| F | 11,500-17,499 |
| G | 0-11,499 |
Ranking rewards[edit]
silver badges will be rewarded each month, based on how your score ranks against other players.
- Per-area score ranking rewards
| Rank | Reward |
|---|---|
| 1-10 | silver badge x1,000
|
| 11-100 | silver badge x500
|
| 101-1,000 | silver badge x400
|
| 1,001-10,000 | silver badge x300
|
| 10,001-30,000 | silver badge x200
|
| 30,001-9,999,999 | silver badge x100
|
- Total score ranking rewards
| Rank | Reward |
|---|---|
| 1 | silver badge x3,000, "Underside MVP" title
|
| 2 | silver badge x3,000, "Proven Strength" title
|
| 3 | silver badge x3,000, "A True Secret Trick" title
|
| 4-10 | silver badge x3,000, "Famous Behind the Scenes" title
|
| 11-100 | silver badge x1,500
|
| 101-9,999,999 | silver badge x1,000
|
Special Skills[edit]
Some skills have special effects that only activate in Hell's Park Underside. Some of these skills are further restricted to only a specific area of HPU, and/or are exclusive to certain demons.
| Type | Name | Specific area? | Exclusive? | Notes |
|---|---|---|---|---|
 Passive |
Pixie (Underside) | - |  Pixie |
Available through silver badges in Jan 2025.
|
| Passive |
Illuyanka (Underside) |  Grave Area only |
 Illuyanka |
|
| Passive |
Koumokuten (Underside) |  Kawara Area only |
 Koumokuten |
Available through silver badges in Mar 2025.
|
| Passive |
Baphomet (Underside) |  Spike Hell Area only |
 Baphomet |
Available through silver badges in Apr 2025.
|
| Passive |
Arianrhod (Underside) |  Sanzu River Area only |
 Arianrhod |
Available through silver badges in May 2025.
|
| Passive |
Dominion (Underside) |  Blood Pond Area only |
 Dominion |
Available through silver badges in Jun 2025.
|
| Passive |
Jack Frost (Underside) | - |  Jack Frost |
Available through silver badges (Jun 2025 onwards)
|
| Passive |
Scathach (Underside) |  Hell Cafe Area only |
 Scathach |
Available through silver badges in Jul 2025.
|
| Passive |
Shiki-Ouji (Underside) |  Sanzu River Area only |
 Shiki-Ouji |
Available through silver badges in Aug 2025.
|
| Passive |
Mermaid (Underside) | Spike Hell Area only |
 Mermaid |
Available through silver badges in Sep 2025.
|
| Passive |
Baihu (Underside) | Burning Area only |
 Baihu |
Available through silver badges in Oct 2025.
|
| Passive |
Kaiwan (Underside) | Blood Pond Area only |
 Kaiwan |
Available through silver badges in Nov 2025.
|
| Passive |
Efreet (Underside) | Hell Cafe Area only |
 Efreet |
Available through silver badges in Dec 2025.
|
| Passive |
Lailah (Underside) | Kawara Area only |
 Lailah |
Available through silver badges in Jan 2026.
|
| Passive |
Tam Lin (Underside) | Grave Area only |
 Tam Lin |
Available through silver badges in Feb 2026.
|
| Passive |
Horkos (Kawara: Underside) | Kawara Area only |
 Horkos |
Available through silver badges in Mar 2026.
|
| Passive |
Horkos (Spike Hell: Underside) | Spike Hell Area only |
Horkos |
Available through silver badges in Mar 2026.
|
| Passive |
Tiamat (Underside) | Sanzu River Area only |
 Tiamat |
Available through silver badges in Apr 2026.
|
| Passive |
Chimera (Underside) | Blood Pond Area only |
 Chimera |
Available through silver badges in May 2026.
|
| Passive |
Mitra (Underside) | Hell Cafe Area only |
 Mitra |
Available through silver badges in Jun 2026.
|
| Passive |
Fortunate Park Visitor | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Phys |
Struggle Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Fire |
Trisagion (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Fire |
Fiery Soul Prison (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Fire |
Fire Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Ice |
Ice Age (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Ice |
Frozen World (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Ice |
Ice Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Elec |
Thunder Reign (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Elec |
Thunderous Advent (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Elec |
Thunder Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Force |
Killing Wind (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Force |
Turbulent Advent (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Force |
Wind Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Light |
Thunderclap (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Light |
Divine Massacre (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Light |
White Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Dark |
Hell Gaze (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
| Dark |
Eternal Hell (Underside) | - | - | 3000 B Coins from Aura Gate 0 |
| Dark |
Black Slash (Underside) | - | - | Rare drop from Hell Genome Cube (costs silver badges)
|
Rewards[edit]
Friendship Badge shop[edit]
Gold badges[edit]
| Exchange Lineup | Gold badge cost |
Cap |
|---|---|---|
  Lost Name |
600 | 1 |
 Lost Name Spirit × 10 (1st set) |
100 | 10 |
| Lost Name Spirit × 10 (2nd set) |
150 | 20 |
| Lost Name Spirit × 10 (3rd set) |
200 | 30 |
 Transcend Stone for Lost Name × 1 (1st set) |
100 | 94 |
| Transcend Stone for Lost Name × 1 (2nd set) |
200 | 88 |
Notes:
- Initially only Lost Name is available, but after buying him, the spirit and transcend options are unlocked.
- Each set of spirits is unlocked after the previous set is exhausted. The same concept applies to the transcend stones.
- Panel 1 costs 1,000 badges, Panel 2 costs 3,000 badges, and Panel 3 costs 6,000 badges, totaling 10,000 badges to get the first 3 panels.
- Gold badge income is 690 per month (230 per area) if you clear level 10 of each area.
- There are only enough spirits to reach Panel 3 from scratch, not Panel 4. Getting Panel 4 will require pulling gacha dupes of Lost Name.
Silver badges[edit]
| Exchange Lineup | Silver badge cost |
Cap |
|---|---|---|
 Hell Genome Cube × 1 |
1,000 | No Cap |
 Pixie (Underside) Genome |
3,000 | 1 (rotating) |
| Illuyanka (Underside) Genome |
3,000 | 1 (rotating) |
| Koumokuten (Underside) Genome |
3,000 | 1 (rotating) |
| Baphomet (Underside) Genome |
3,000 | 1 (rotating) |
| Arianrhod (Underside) Genome |
3,000 | 1 (rotating) |
| Dominion (Underside) Genome |
3,000 | 1 (rotating) |
| Jack Frost (Underside) Genome |
3,000 | 1 |
| Scathach (Underside) Genome |
3,000 | 1 (rotating) |
| Shiki-Ouji (Underside) Genome |
3,000 | 1 (rotating) |
| Mermaid (Underside) Genome |
3,000 | 1 (rotating) |
| Baihu (Underside) Genome |
3,000 | 1 (rotating) |
| Kaiwan (Underside) Genome |
3,000 | 1 (rotating) |
| Efreet (Underside) Genome |
3,000 | 1 (rotating) |
| Lailah (Underside) Genome |
3,000 | 1 (rotating) |
| Tam Lin (Underside) Genome |
3,000 | 1 (rotating) |
| Horkos (Kawara: Underside) Genome |
3,000 | 1 (rotating) |
| Horkos (Spike Hell: Underside) Genome |
3,000 | 1 (rotating) |
| Tiamat (Underside) Genome |
3,000 | 1 (rotating) |
| Chimera (Underside) Genome |
3,000 | 1 (rotating) |
| Mitra (Underside) Genome |
3,000 | 1 (rotating) |
 Sword of Kusanagi 5★ |
100 | 20 / Month |
 Yata Mirror 5★ |
500 | 5 / Month |
 Yasaka Magatama 5★ |
200 | 5 / Month |
 Kasane Magatama |
3,000 | 2 / Month |
 Aether Crystal |
1,500 | 1 / Month |
 Skip Ticket (Sin) x20 |
3,000 | 1 / Month |
 Essence of Sin x160 |
2,000 | 2 / Month |
 Mitama Extract St x10 |
300 | 5 / Month |
 Mitama Extract Ma x10 |
300 | 5 / Month |
 Mitama Extract Vi x10 |
300 | 5 / Month |
 Mitama Extract Ag x10 |
300 | 5 / Month |
 Mitama Extract Lu x10 |
300 | 5 / Month |
 Blank Genome |
1,500 | 2 / Month |
 6★ Brand Cube |
500 | 10 / Month |
- Silver badge income is 7,200 per month (2,400 per area) if you clear level 10 of each area.
- If you clear level 20 of each area, add 9,000 (3,000 per area) to that.
- Each set of 10 levels from level 21-100 gives 1,500 (500 per area).
- Each set of 10 levels from level 101+ gives 300 (100 per area).
- Assuming you are in the lowest ranking tier, you can expect another 1,300 per month (1,000 for total score, plus 100 per area).
Hell Genome Cube[edit]
The Hell Genome Cube gives a random skill genome from a very large pool. A few of the skills are rare and exclusive:
| Genome | Notes |
|---|---|
| Fortunate Park Visitor |
Rare, exclusive |
| Struggle Slash (Underside) |
Rare, exclusive |
| Trisagion (Underside) |
Rare, exclusive |
| Fire Slash (Underside) |
Rare, exclusive |
| Ice Age (Underside) |
Rare, exclusive |
| Ice Slash (Underside) |
Rare, exclusive |
| Thunder Reign (Underside) |
Rare, exclusive |
| Thunder Slash (Underside) |
Rare, exclusive |
| Killing Wind (Underside) |
Rare, exclusive |
| Wind Slash (Underside) |
Rare, exclusive |
| Thunderclap (Underside) |
Rare, exclusive |
| White Slash (Underside) |
Rare, exclusive |
| Hell Gaze (Underside) |
Rare, exclusive |
| Black Slash (Underside) |
Rare, exclusive |
Rotation history[edit]
3 areas are available per month, with the available areas and their challenge conditions rotating each month. The demon-specific Underside skill in the shop also rotates each month.
| Month | Challenge type | Shop genome
| ||
|---|---|---|---|---|
| Fusibles | Race | Low-grade | ||
| Jan 2025 | Spike Hell (Fire)
|
Kawara (Phys) (Kishin, Genma, Night) |
Grave (Ice)
|
Pixie (Underside)
|
| Feb 2025 | Spike Hell (Fire)
|
Kawara (Phys) (Kishin, Genma, Night) |
Grave (Ice)
|
Illuyanka (Underside)
|
| Mar 2025 | Kawara (Phys)
|
Spike Hell (Fire) (Beast, Vile, Tyrant) |
Sanzu River (Light)
|
Koumokuten (Underside)
|
| Apr 2025 | Blood Pond (Elec)
|
Sanzu River (Light) (Holy, Megami, Deity) |
Spike Hell (Fire)
|
Baphomet (Underside)
|
| May 2025 | Sanzu River (Light)
|
Hell Cafe (Force) (Lady, Genma, Avian) |
Blood Pond (Elec)
|
Arianrhod (Underside)
|
| Jun 2025 | Hell Cafe (Force)
|
Blood Pond (Elec) (Megami, Night, Divine) |
Kawara (Phys)
|
Dominion (Underside)
|
| Jul 2025 | Grave (Ice)
|
Kawara (Phys) (Kishin, Fairy, Fiend) |
Hell Cafe (Force)
|
Scathach (Underside)
|
| Aug 2025 | Kawara (Phys)
|
Sanzu River (Dark) (Tyrant, Vile, Brute) |
Grave (Ice)
|
Shiki-Ouji (Underside)
|
| Sep 2025 | Sanzu River (Dark)
|
Grave (Ice) (Dragon, Femme, Megami) |
Spike Hell (Force)
|
Mermaid (Underside)
|
| Oct 2025 | Burning (Elec)
|
Spike Hell (Force) (Megami, Genma, Avian) |
Sanzu River (Dark)
|
Baihu (Underside)
|
| Nov 2025 | Spike Hell (Force)
|
Blood Pond (Dark) (Vile, Fallen, Night) |
Burning (Elec)
|
Kaiwan (Underside)
|
| Dec 2025 | Blood Pond (Dark)
|
Burning (Elec) (Holy, Deity, Kishin) |
Hell Cafe (Fire)
|
Efreet (Underside)
|
| Jan 2026 | Kawara (Light)
|
Hell Cafe (Fire) (Fiend, Vile, Herald) |
Blood Pond (Dark)
|
Lailah (Underside)
|
| Feb 2026 | Hell Cafe (Fire)
|
Grave (Force) (Genma, Dragon, Megami) |
Kawara (Light)
|
Tam Lin (Underside)
|
| Mar 2026 | Grave (Force)
|
Kawara (Light) (Tyrant, Kishin, Fury) |
Spike Hell (Phys)
|
Horkos (Kawara: Underside)
|
| Apr 2026 | Sanzu River (Ice)
|
Spike Hell (Phys) (Lady, Beast, Genma) |
Grave (Force)
|
Tiamat (Underside)
|
| May 2026 | Spike Hell (Phys)
|
Sanzu River (Ice) (Deity, Snake, Drake) |
Blood Pond (Elec)
|
Chimera (Underside)
|
| Jun 2026 | Hell Cafe (Dark)
|
Blood Pond (Elec) (Fiend, Deity, Fallen) |
Sanzu River (Ice)
|
Mitra (Underside)
|
| Jul 2026 | Blood Pond (Elec)
|
Hell Cafe (Dark) (Vile, Deity, Reaper) |
 Burning (Fire)
|
Pele (Underside)
|
| Aug 2026 |  Kawara (Light)
|
Burning (Fire) (Lady, Beast, Dragon) |
Hell Cafe (Dark)
|
Kresnik (Underside)
|
| Sep 2026 | Burning (Fire)
|
 Grave (Phys)(Fairy, Kishin, Fiend) |
Kawara (Light)
|
Setanta (Underside)
|
| Oct 2026 | Grave (Phys)
|
Kawara (Light) (Avatar, Genma, Tyrant) |
 Spike Hell (Force)
|
Isis (Underside)
|
Guide pages[edit]
| Hell's Park Underside
| |||||||
|---|---|---|---|---|---|---|---|
| Area | Phys |
Fire |
Ice |
Elec |
Force |
Light |
Dark
|
 Spike Hell
|
Spike Hell (Phys) |
Spike Hell (Fire) |
- | - | Spike Hell (Force) |
- | |
 Kawara
|
Kawara (Phys) |
- | - | - | - | Kawara (Light) |
- |
 Grave
|
- | - | Grave (Ice) |
- | Grave (Force) |
- | - |
 Sanzu River
|
- | - | Sanzu River (Ice) |
- | - | Sanzu River (Light) |
Sanzu River (Dark)
|
 Blood Pond
|
- | - | - | Blood Pond (Elec) |
- | - | Blood Pond (Dark)
|
 Hell Cafe
|
- | Hell Cafe (Fire) |
- | - | Hell Cafe (Force) |
- | Hell Cafe (Dark)
|
 Burning
|
- | Burning (Fire) |
- | Burning (Elec) |
- | - | - |
| Quest Areas | |
|---|---|
| Permanent Content | Story • Dx2 Quests • Alter-World • Aura Gate (1, 2, SP) |
| Farming Quests | Strange Signal • Brands of Sin • Wanted |
| Recurring Events | Hell's Park (Underside) • Advent • Kiwami • Tokyo Abyss • Take Back Tokyo • Demon Alliance Invasion |
| Competitive Content | Democalypse • Dx2 Duel • Battle Tower • Dx2 Battle Tournament |
| Retired Events | Eclipse |