Deep nightmare - Seven Knights Idle Adventure

Deep Nightmare is a game mode where you must face bosses, one boss per tier, with three different teams.
To pass the stage, you must defeat the boss with each of your teams.

How to unlock it

You unlock Deep Nightmare once you have completed tier 30 of Nightmare mode.

Information

The Nightmare shard bonuses are also active in this game mode.
There is no access limit in this mode; you can restart a battle an infinite number of times.

Each team consists of 15 heroes. Depending on the number of tiers you manage to pass, this mode can become your main source of elixir.

Currently, this game mode is the most time-consuming because you cannot skip battles.
In addition, you must complete 3 battles per tier.

Fortunately, the developers are working on a solution: More information in this developer note.

Tips

You must defeat the boss with each of your teams, so you need to build 3 balanced teams.

Note that the further you progress, the more the boss will have dodge and critical resistance.

Each of your teams must have the core buffs and debuffs:

In addition, it is important to have one hero per team who boosts damage against bosses in Nightmare mode:

• High Lord Alicia (+100% final damage against Nightmare Boss)
• Transcendent Witch Velika (+100% damage nightmare Boss)
• Medea (+50% damage nightmare Boss)
• Alcyion (+50% damage nightmare Boss)
• High Lord Sun Wukong (+70% damage nightmare Boss)
• High Lord Orly (+80% damage nightmare Boss)

Some bosses have a healing buff, so it's also important to choose a hero who can remove buffs from bosses.
Equip each team with one or more heroes with attacks that hit multiple times, as some bosses have a veil buff (20 attacks canceled).

Raise your Nightmare Shard level (or rather, wait for it to rise).

Solve the critical hit resistance problem.

At first, critical hit resistance will not pose any problems, but it will quickly prove to be a real challenge.

Critical hit rate resistance on boss

This type of game mode is why it's useful to have heroes with critical hit potential rolls.

Since the release of the Awakening heroes, add a hero with a 36% critical hit rate buff, such as Awakening Rachel.

Add a hero that applies the debuff reducing critical hit rate resistance to 36%, such as Bloody Night Kyle or Cat Mage Lucia.

Wait for level 30 of Nightmare shard to get a critical hit rate increase to 50% for all of your heroes.

The hardest part is often applying the first decrease critical hit rate resistance debuff.
This is because at the start of the battle, your heroes are not buffed and may miss their critical hits and therefore fail to apply their buffs.
(Of course, this is in cases where the hero's buffs are applied via critical hits.)

Use aura

The solution is to use a hero with an aura that increases the crit rate.
This will increase the crit hit rate for all heroes without having to touch the boss, so more chances to apply decrease critical hit resistance.
Vicky is the only hero with this ability.

Use active skill

An another solution is to use a hero with a decrease crit rate resistance debuff on their active skill.
Even if it is 20% (instead of 24%), this will allow you to rely solely on your accuracy to apply the debuff.
In the case of a reduction to only 20%, it is still important to have a second hero at 24%.

Michaela and Taka have this ability.

Strategy against bosses

First essential point for your survival: include a healer in each of your teams. To maximize your damage output, every team should have a hero capable of applying the Overload debuff, which gradually drains your HP. Without a healer to compensate, you risk getting wiped out before even reaching the boss.

Unlock these heroes as you progress:

Skuld,

Undercover Ruri,

Ecila in Dreamland.
Otherwise, make sure you have enough raw damage to kill the boss before Overload or the boss itself finishes you off.

Tier 1 to 100

This first bracket is essentially a test of your heroes' critical hit rate. If your heroes are properly build, tiers are cleared fairly smoothly. As long as your teams are balanced, even with modest damage, you shouldn't hit any major wall.

Tier 100 to 200

This is the range, and more specifically between tiers 100 and 180, where you can no longer afford to ignore each boss's specific mechanics. Some of them will force you to rework your team compositions to get through without trouble.
At this level, monsters have a 178% critical hit resistance, so prepare accordingly.

The most challenging fights in my experience are bosses that can remove your buffs in AOE or apply crowd control in AOE.

Strategy against debuffer bosses

The approach here is the same as for the Hard Boss Challenge: protect yourself with nullify damage (veil) across your teams, which prevents the boss from stripping your buffs when it attacks.
Look toward the following heroes: Arang, Restia, Ecilia, Elenia or Awakened Karma.

Deep nightmare Boss with strip buffs

Strategy against crowd control

To counter control effects, the technique of fielding a team that applies Veil proves particularly effective. You can also slot in heroes that grant your team immunity to crowd control effects.

Be warned: every 10 tiers you will face a boss Endymion's illusion that applies Paralysis in AOE. This boss uses multi-hit attacks, which means nullify damage will unfortunately not protect you from its crowd control.

Endymion's illusion skills: Paralysis with multi-hit

This is where heroes with paralysis immunity become strongly recommended, if not mandatory, with at least one per team:

• 
  Undercover Ruri
• 
  Lania
• 
  Herald of Peace Rauha

I don't have all of these heroes, what should I do?

For Undercover Ruri and Lania, they are fairly easy to obtain and work even at 0 stars. Level them up to 100 regardless so they can take a hit.
For Rauha, if like me you don't yet have the resources to awaken him, the strategy is to place your best DPS in the team that lacks immunity, compensating for that gap through sheer damage output.

Tier 200+

From this point on, you will only encounter one type of enemy Endymion's illusion: the one applying paralysis. Keep the same team composition, and progression becomes purely a matter of stats.

A fight againts Endymion's illusion

Teams Deep nightmare (Update January 2026)

I use a general team so that I can take on all bosses and save time.

There is not much to add about the teams; they are simply teams created based on the Tips section above.

To optimize further, you can create a team for each type of boss.

Rewards

For each tier you complete, you will receive 300 elixirs and 300 power tokens.
Every 10 tiers, you will receive a copy of the hero Alcyion.

From tier 100 onwards, power tokens are replaced by 5,000 gold dice.

From tier 200 onwards, gold dice are replaced by Abyss Destroyer's Tokens.

Reset

Please note that progress in this game mode is reset every 14 days after the update, as in Nightmare mode.

FAQ