Hell's Park Underside/Sanzu River Area/Ice

Combat stats use the screenshot’s level, STR, MAG and VIT with the base stat formulas. Enemy skill bonuses are not included. HP is the recorded maximum.

Sources

Recommended demons

Follow the selected challenge’s roster/archetype rules. Special bonuses require the matching Underside skill, not merely the same demon name. Kill Nidhoggr first, Chatterskulls next and Ixtab last. Keep Evade Mortal active; uncontrolled area follow-ups can cause a wipe.

Earlier recommended alternatives

Queen MabBanner exclusive

Secondary weakness option

The guide identifies Elec damage for Nidhoggr’s weakness. Check roster rules and avoid accidental premature kills of the other enemies.

Earlier recommended alternatives

ApsuBanner exclusive

Banner: controlled Ice damage

Use the signature single-target Ice attack to remove Nidhoggr before the skulls, then finish Ixtab last. This avoids choosing an uncontrolled area carry for a strict kill-order fight.

Needs: Build the appropriate attack stat and MP; retain the guide’s Evade Mortal provider. Banner option for unrestricted clears only; not legal for a fusible-only or 4★-only challenge.

Watch for: Check every automatic follow-up in the whole team. Revive sealing, mitigation and Null Mortal do not let you ignore Ixtab’s fixed-damage death trigger.

Earlier recommended alternatives

TiamatAlternative

Area-specific Mortal protection

The matching Underside skill recasts Evade Mortal at turn start, with its stated battle limit. Keep the demon alive and refresh protection when needed.

Earlier recommended alternatives

Jack FrostAlternative

Controlled elemental alternative

With Jack Frost (Underside), use a single-target Ice transfer. Avoid area chain variants that kill Ixtab early.

Kit-based options; tested clears remain in the guide’s team section.

Skills on multiple demons:

Phys Pierce [weak] Underside

Used by: Chatterskull, Nidhoggr

Gains Phys Pierce. Damage received by enemy through this skill is reduced by 70% if the enemy has Null, Repel or Drain Phys attribute.

Source

Dark Pierce [weak] Underside

Used by: Chatterskull, Ixtab

Gains Dark Pierce. Damage received by enemy through this skill is reduced by 70% if the enemy has Null, Repel or Drain Dark attribute.

Source

Hell Recovery

Used by: Chatterskull, Ixtab, Nidhoggr

Adds Null Bind/MortaI. +80% to hit rate. +300 to Phys ATK and Mag ATK. +300% to status ailment auto recovery rate.

Source

Hell Ultra Booster

Used by: Chatterskull, Nidhoggr

+20% to Max HP. +100 to Phys ATK and Mag ATK. +25% to damage dealt. +100% to Healing skill effectiveness.

Source

Hellsent: Phys

Used by: Chatterskull, Nidhoggr

+40% to Max HP.. +100 to Phys ATK and Mag ATK.

Activates the following Chain Effect at the start of every second turn of the skill holder: Inflicts high-accuracy Phys damage (Physical, Power: 200) with a Bulwark-piercing effect and a 100% critical hit rate on all enemies.

Source

Hellsent: Dark

Used by: Chatterskull

+40% to Max HP.. +100 to Phys ATK and Mag ATK.

Activates the following Chain Effect at the start of every second turn of the skill holder: Inflicts high-accuracy Dark damage (Physical, Power: 200) with a Bulwark-piercing effect and a 100% critical hit rate on all enemies.

Source

Skills on Chatterskulls only:

Vengeance Blow

Used by: Chatterskull

Activates the following Chain Effect when downed during the enemy turn: Inflict Almighty (Power: 150) damage to the attacker, with 100% chance to inflict Mortal. Nullifies all death prevention skills. Won't activate when your party is wiped out.

Source

Skills on Ixtab only:

Yaxche [Underside]

Used by: Ixtab

Activates the following Chain Effect when the skill holder is downed: Inflicts 10,000 damage with a Bulwark-piercing effect 4 times to all enemies, with a 100% chance to inflict Mortal while ignoring all death prevention skills. However, this effect will not activate if the party is wiped out.

Source

Hell Mega Booster

Used by: Ixtab

+30% to Max HP. +200 to Phys ATK and Mag ATK. +50% to damage dealt. +200% to Healing skill effectiveness.

Source

Hellbound: Dark

Used by: Ixtab

+50% to Max HP.. +200 to Phys ATK and Mag ATK.

Activates the following Chain Effect at the start of enemy turn: Place 5 counts of Spirit Chains of Suppression on all enemies. (Once per battle)

Activates the following Chain Effect at the start of every third turn of the skill holder: Inflicts high-accuracy Dark damage (Physical, Power: 300) with a Bulwark-piercing effect and a 100% critical hit rate on all enemies.

Source

Skills on Nidhoggr only:

Nastrond [Underside]

Used by: Nidhoggr

Activates the following Chain Effect when an ally is downed: Restores 80% HP to the skill holder, then grants the skill holder a Bulwark with 20% of their HP. (1 turn)

Activates the following Chain Effect at the end of enemy turn: Revives a random downed ally with 100% HP.

Source

Explanation

• Hellbound: Dark will apply 5 stacks of Spirit Chains of Suppression to you.
• Vengeance Blow - When a Chatterskull is killed, it will cast an Almighty hit with Mortal on their attacker.
• Nastrond Underside - When an enemy dies, Nidhoggr gets a full heal and a 20% HP Bulwark. When your turn ends, a random enemy gets revived at 100% HP.
• Yache Underside - When Ixtab is killed, she will deal 4 AoE hits of 10,000 fixed damage + Mortal, which also pierce Bulwarks and ignore endures. The gist is that she will wipe your party unless she dies last.
• If the adds are not dead at the start of their second turn, they will hit you with a bulwark-piercing, 100%-crit enrage AoE. Ixtab will do one too, if she isn't dead by her third turn.

Arianrhod (Underside) effect overview

• Self gets 50% HP, 180% Ice damage, 20% accuracy, 3 MP discount for Ice skills, and immunity to Spirit Chains of Suppression.
• The team gets 30% Ice damage and 30% accuracy.
• At the start of your team's turn, your entire team gets Evade Mortal (up to 3 times per battle). This saves a Press Turn you would've needed to spend on casting Tetraja.

Colors

• Clear for the fusibles ruleset.
• Red for Bufudyne. This frees up the transfer slot to run a damage booster.

Skill Transfer

• Ice Age is ideal, otherwise use the highest-damage single-target attack skill you have, such as Bufudyne (from Red or transferred).
  • However, using Ice Age (Underside) is risky, as its AOE might kill the Chatterskulls before Nidhoggr. Due to this, single-target attacks are preferred for consistency.
• Red should use a damage booster, such as Ice Amp or Ice Boost. If Ice Age becomes available, then use that attack instead of a damage booster.

Brands

• MATK% Spell.
• Due to her MP discount, Divine's MP regen is probably not necessary.

Misc notes

• Generally speaking: If Bufudyne will be your main attack, use Red. If you have Ice Age, use Clear.
• She also has a 150% healing boost, but it isn't very helpful in practice. Stick with your healing items.
• She must be alive at the start of a turn in order to grant Evade Mortal.

Jack Frost (Underside) effect overview

• Self gets 15% Ice/Light damage, and Concentrate (2.25x damage) on his first action - together, these are 87% damage on average across his 2 actions on the first turn. Also gets 50% HP and immunity to Spirit Chains of Suppression.
• If an ally uses an Ice/Light skill, Jack Frost automatically casts ATK Buff (up to 3 times per turn).

Colors

• Clear for the fusibles ruleset. It also gives Hama, which can be useful in Light areas of HPU.
• Red for Bufula, as it's stronger than his innate Bufu.

Skill Transfer

• Jack Frost does not have any MP discounts, so 7 MP skills such as Ice Age may be too expensive to cast repeatedly.
  • Ice Age (Underside) starts at 7 MP, then becomes 6 MP at max level. This is the strongest skill he can use, but the cost of maxing it is very high.
  • However, using Ice Age (Underside) is risky, as its AOE might kill the Chatterskulls before Nidhoggr. Due to this, single-target attacks are preferred for consistency.
• Clear can level up Bufu and transfer a damage booster, but transferring level 1 Bufudyne will do more damage.
• Red should level up Bufula and transfer a damage booster, such as Ice Amp, Merciless Blow, or Ice Boost. This will outdamage a transferred Bufudyne.
• Bufu, Bufula, Mabufu, and Hama can all be leveled cheaply - run Chapter 1 Leveling Quest for Slimes to feed him for skill points, then transfer skill dupes from 1★-3★ to level his skills.

Brands

• MATK% Spell or Divine.

Misc notes

• If using Ice Age (Underside), then Concentrate only affects the initial hit, not the AoE chain.
• Consider transcending him for skill switches, as that lets him easily swap builds between multiple areas.

Team restrictions:

Difficulty	Restriction
Lv 3-5	3 or more demons must be fusible*.
Lv 6-8	4 or more demons must be fusible.
Lv 9+	All 5 demons must be fusible.
Lv 6+	1 or more demons must be grade 79 (4★ base) or lower.
Lv 9+	1 or more demons must be Clear .

Notes regarding fusibles:

• Multi-fusions count.
  • Beelzebub☆ counts, despite needing a gacha-exclusive material to make him.
  • For limited-time multi-fusions, only the ones that are currently-available will count.
• Pixie and Slime count, even though you cannot fuse them.

Sample party

Tiamat Skills Tiamat (Underside) Ice Age Brands MATK% Spell Requirements -

Indrajit Skills Elec Amp Elec Boost Brands PATK% Divine or Spell Requirements -

Anat Skills Serial Killer Elec Boost Brands MATK% Divine or Spell Requirements -

Izanami Skills Maziodyne Elec Boost Brands MATK% Divine or Spell Requirements -

Thor Skills Maziodyne Elec Amp Brands MATK% Divine or Spell Requirements -

Team notes:

• If you don't have Tiamat, put Tetraja on your fastest unit, so you can cast it ASAP.
• We focus on Elec AoE to kill Nidhoggr first, while lightly damaging the Chatterskulls. Ice AoE is not recommended, as it will probably kill the skulls too quickly. Most of the fusible Ice options are AoE, and they don't have as much synergy as the Elec options.
• Anat: Deals a lot of AoE Elec damage, plus Thunderstorm applies ATK Debuff and DEF Debuff.
  • The Spirit Chains of Suppression prevent Anat from wasting her Concentrate on her random-hit chain effect, meaning she can use it to spam every second Thunderstorm instead.
• Anat and Izanami both boost the team's Elec damage, and grant a total 2 MP discount for the team's Elec skills.
• Thor has Maziodyne transferred, as this is more consistent than Mjolnir in hitting Nidhoggr while splashing damage on everyone else. Clear is viable if you happen to have one, as that comes with Maziodyne innately.

Other options worth considering:

Flexible:

• Ishtar: Mesopotamian Star sets up buffs and debuffs (both for offense, and for helping survive Ixtab's attacks), then she can switch to using a transferred attack afterwards. Might need Resist Dark, especially if not P3 for the HP boosts.
• Succubus: 204 magic. Bufudyne and Mazionga.
• Titania: 235 magic, has Elec Boost, Purple has Back Attack. Mazionga. Can also transfer Bufudyne + Ice Boost to allow her to damage Ixtab more.
• Anubis: 217 magic, Purple has Merciless Blow. Transfer Bufudyne + Ice Boost. Can run Elec transfers instead, if desired.

Elec AoE users:

• Anzu: 170 magic, Purple has Elec Boost and P3 has 10% Elec damage. Mazionga. War Cry for ATK and DEF Debuffs.
• Tlaltecuhtli: 184 magic, Purple has Elec Boost, P3 has 8% Elec damage, Earth Sacrifice levels have 10% Elec damage. Mazionga.
• Lilith: 190 magic. Maziodyne.
• Beelzebub: 184 magic (p1). Mazionga.

Ice single-target users:

• Hresvelgr: 180 magic, has Ice Boost, North Wind levels have 15% Ice damage, P3 has 20% Ice damage aura. Bufudyne. Purple has Auto-Rakunda to apply a 3-turn DEF Debuff. Will need Resist Phys. North Wind won't activate due to Suppression, so he can safely use Bufudyne to hit just 1 target at a time.
• Beiji-Weng: 186 magic, has Ice Boost, P3 has 10% Ice damage. Bufudyne.
• Ym: 199 magic, has Ice Boost, Purple has Back Attack, P3 has 10% Ice damage. Will need a single-target transfer. Alternatively, Clear has Bufudyne.
• Gui Xian: 186 magic, has Ice Boost. Bufudyne.
• Black Frost: 201 magic, Purple has Ice Amp. Will need a single-target transfer.
• Sarasvati: 195 magic, P3 has 10% Ice damage, Purple has Back Attack. Will need a single-target transfer. Alternatively, Clear has Bufudyne.
• King Frost: 171 magic, has Ice Boost, P3 has 10% Ice damage. Will need a single-target transfer.
• Loki: 168 magic, P3 has 5% damage. Bufudyne.

Team restrictions:

Sample party

Tiamat Skills Tiamat (Underside) Ice Age Brands MATK% Spell Requirements -

Zeus Skills Elec Survivor Elec Boost Brands PATK% Divine or War Requirements -

Vritra Skills Assassin Elec Boost Brands MATK% Spell Requirements -

Apsu Skills Assassin Ice Boost Brands PATK% Divine or War Requirements -

Ym Skills Merciless Blow Bufudyne Brands MATK% Divine or Spell Requirements -

Team notes:

• Zeus:
• Vritra:
• Apsu:
• Ym: 199 magic, has Ice Boost, Purple has Back Attack, P3 has 10% Ice damage. Will need a single-target transfer. Alternatively, Clear has Bufudyne.

Other options worth considering: Flexible:

• Ardha: Will need an Elec or Ice transfer.
• Lugh: Will need an Elec or Ice transfer.
• Thoth: Will need an Elec or Ice transfer.

Elec users:

• Otohime: bring Elec boosters (via transfers or teammates) to swing her element auto-select towards Elec instead of Ice.
• Odin A:

Ice single-target users:

• Gui Xian: 186 magic, has Ice Boost. Bufudyne.