Chaos Zero Nightmare Great Rift Guide: Current Boss and How to Score High

Chaos Zero Nightmare Great Rift is the game's rotating boss mode, where you bring two parties against one boss and push for the highest score you can manage. The next rotation changes more than the boss. The new Herald of Judgment arrives together with a revamped format that replaces the old difficulty levels with two battle types, one casual and one competitive. At gamemarket.gg, we explain how the Great Rift works now, how to handle Herald of Judgment's Original Sin cards and which kind of deck fits this boss. We update this page every time a new Great Rift boss arrives.

How the Great Rift Works

The Great Rift puts you against a single boss using two separate parties:

• Vanguard: the first party, which fights the opening phase of the boss
• Rearguard: the second party, which takes over for the next phase

Each phase has a turn limit, and your score depends on how much damage you deal before it runs out. Bosses rotate with major updates, so each new boss brings its own gimmick and rewards a different style of deck. The first Great Rift boss, Suppressed Servant, ran in December 2025, and the mode has rotated bosses ever since.

What Changes in the New Great Rift

Starting with the Herald of Judgment rotation, the old Easy, Normal, Hard and Hell difficulty levels are gone. They are replaced by two battle types.

Subjugation Battle

Subjugation Battle is the relaxed way to play the Great Rift.

• No ranking: your results do not count toward the leaderboard
• Both parties can finish the boss: the Vanguard and the Rearguard can each defeat it
• Tier instead of rank: your score gives you a Tier from B to SSS
• No season restrictions: you can use Save Data from any season, so older builds are still useful here

This is the mode to start with, and it is also the key to unlocking the competitive side.

Merit Battle

Merit Battle is the competitive mode. It follows the same rules as the old Great Rift, and your rewards depend on your final rank when the rotation settles.

• Unlock condition: defeat the Rearguard boss in Subjugation Battle for the first time
• Vanguard: can defeat the boss as normal
• Rearguard: the boss has infinite HP, and the fight ends when the turn limit is reached, so this phase is purely about damage
• Season restrictions are back: the Rearguard can only use Save Data from the current season or default Save Data, and season restrictions also apply to Equipment and Cards

The development team brought season restrictions back because players with years of stored Save Data had a growing advantage over new and returning players. Subjugation Battle keeps the freedom to use any build, while Merit Battle aims to be a fairer test of current season strategies.

New Help Before You Fight

Two new features make preparation easier:

• Boss Strategy Page: shows the boss's main attack patterns and how to counter them before you enter
• Recommended Formation: suggests Combatant combinations and Save Data setups for the Vanguard and the Rearguard. You can copy them or save them as Presets

If you are new to the mode, check the Recommended Formation first and adjust it to the Combatants you own.

Current Boss: Herald of Judgment

Herald of Judgment is the boss of the new Great Rift. Its whole fight revolves around [Original Sin] cards that it places in your hand.

How Original Sin Cards Work

• Herald of Judgment carries stacks, and the Original Sin cards are how you remove them
• Every Original Sin card shows a condition for reducing Sin, such as activating non-attack cards, drawing cards or creating cards
• Meeting the condition reduces Sin, which removes the boss's stacks
• The card's Cost drops each time you activate another card. When the Cost reaches 0, it turns into the next Original Sin card

What Happens If You Fail

The punishment is harsh:

• If the boss still has stacks when the Second Original Sin card's Cost reaches 0, or after a certain number of turns
• All cards in your hand are removed
• Herald of Judgment then unleashes a powerful attack

If you clear all of its stacks in time, the boss only uses a relatively weak attack instead.

How to Score High

The development team spelled out the winning pattern directly:

1. Read the condition on the Original Sin card in your hand
2. Meet that condition to remove the boss's stacks before the card cycles out
3. Once the stacks are gone, attack with everything to deal as much damage as possible

This means pure attack decks will struggle. Decks that can draw cards, create cards or play non-attack cards without losing tempo are better suited to this boss. Draw-heavy engines, like the one in our Diana discard loop build, are the kind of setup that can satisfy these conditions while still building toward damage.

Combatant to Watch: Blazebell

The new Combatant Blazebell, a support-focused Justice Controller, arrives in the same update. Her kit stands out for this boss, in our view, because it creates and draws cards constantly:

• Blue Flame heals and stacks Bind. At 4 Bind stacks it becomes Fluttering Embers, a 0-Cost card that grants 1 AP and draws a card when your hand holds only cards of the same attribute
• Freya's Blessing heals and creates 2 Blue Flame cards
• Resonating Flame creates 3 Blue Flame cards, then 1 more at the start of every turn
• Flame Touch inflicts Melting, which raises the damage enemies take from Justice Cards. After 3 Justice hits, it adds Hypermelting for even more damage

Her card creation and draws line up with two of the Original Sin conditions, and Melting rewards a Justice damage dealer once the stacks are cleared. We will confirm how well she performs once the boss is live.

Rewards

In earlier rotations, Great Rift rewards came from three sources:

• Achievement rewards for reaching score thresholds in a single run
• Weekly rewards based on the total points from all your runs that week
• Leaderboard rewards based on your best score compared with other players

With the revamp, Merit Battle keeps rank-based rewards at settlement, while Subjugation Battle gives a Tier from B to SSS. The exact reward lists for the Herald of Judgment rotation have not been announced yet, and we will add them here once the update is live.

Tips for Your First Run

• Clear Subjugation Battle first. Beating its Rearguard boss is what unlocks Merit Battle
• Use older Save Data in Subjugation. There are no season restrictions there, so your best builds from past seasons are still fair game
• Prepare current season Save Data for Merit Battle. The Rearguard only accepts this season's Save Data or default Save Data
• Keep a non-attack card or a draw effect in hand when an Original Sin card appears, so you can meet its condition before it cycles out
• Save your burst for after the stacks are gone. Damage dealt while the boss still has stacks matters less than avoiding the hand wipe

If you just pulled a damage dealer from the current rate-up, our Tiphera build guide covers how to turn her into a reliable carry. For everything else still running from the anniversary, our 1st Anniversary events guide lists every event and reward.

If you want an account with more Combatants already unlocked, you can explore trusted Chaos Zero Nightmare Accounts, keep your daily runs and events on track with reliable Chaos Zero Nightmare Hourly Services, or push your Great Rift score faster through dependable Chaos Zero Nightmare Boosting.

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