Seven Deadly Sins: Grand Cross Game Wiki

Training Grotto Feat.jpg

Unlocked after Episode 109 of the Story Mode, the Training Grotto is the source of these 3 valuable items used to boost equipment stats:

Item Image Use
Equipment Engraving Stone Icon equipment engraving stone.png Upgrade Equipment to UR
Hammer of Vaizel Icon hammer of vaizel.png Randomly increases the value of bonus stats
Anvil Icon anvil.png Randomly change an equipment’s bonus stats

To get these rewards, you have to win several boss fights with varying difficulties from Level 1-3 Goddess Ambers. Although there are a total of 30 Goddess Ambers at play, you are only allowed to do a maximum of 9 Goddess Amber battles.

Before we proceed to the specifics, check out the general info page if you are not yet familiar with the mechanics of the Training Grotto.

Winning in higher difficulties will cause the gauge at the top of your screen to fill faster. Once filled to 100%, an Illusion Amber will appear for a chance to acquire more rewards. As the name implies, an Illusion Amber creates an illusion of a team you previously used in battle.  

Below is the list of information you need to know before moving on to the strategy part:

  • Each hero can only enter the battle once. Meaning, heroes who have participated and cleared the stage may not be set to the team again.
  • That being said, you have to be careful about which heroes to select on your team. Overkilling one stage may cause you to lose future battles. The key is to use the recommended heroes listed in this guide.
  • Equipment stats are not applied to heroes in the Training Grotto. The Combat Class is only determined by their hero level, awakening level, ultimate level, and costumes.
  • More rare rewards such as Equipment Engraving Stones can be acquired from Illusion Ambers. Maximum rewards can only be achieved by doing level 3 Goddess Amber fights.

Reward Information

Lv. 1 Lv. 2 Lv. 3 Illusion Amber
Combat Class 60,000 75,000 90,000
Fill amount 17.3% 21.4% 34.5% N/A
Stamina 4 6 8 10/15/20
Clear Reward Icon amber key.png Icon amber key.png Icon amber key.png Icon equipment engraving stone.png
x1 x2 x3 x1/2/3
Gold Box Chance 15% 22.5% 30% 50%
Silver Box Chance 35% 45% 47.5% 50%
Bronze Box Chance 50% 32.5% 22.5%
Gold Box Icon hammer of vaizel.png x1 Icon hammer of vaizel.png x1 Icon hammer of vaizel.png x1 Icon hammer of vaizel.png x1
Icon equipment engraving stone.png x3
Silver Box Icon anvil.png x3 Icon anvil.png x6 Icon anvil.png x9 Icon anvil.png x6
Icon evolution stone 04.png x2 Icon evolution stone 04.png x3 Icon evolution stone 04.png x5 Icon equipment engraving stone.png x2
Bronze Box Icon evolution stone 03.png x3 Icon evolution stone 03.png x6 Icon evolution stone 03.png x9
Icon upgrade stone 01.png x10 Icon upgrade stone 01.png x30 Icon upgrade stone 01.png x50

Battle Approach / Strategy

As much as possible, aim to battle Level 3 Goddess Ambers to maximize the rewards.

Boss Affinity Approach Strategy
Hendrickson.png Attribute speed.png HP increase
  • Use Green Meliodas' Outburst Counter when he reaches half HP
Obsessed Knight.png Attribute speed.png Burst
  • Green Valenti and Green Jericho will be your main damage dealer. In case one dies the other will have the opportunity to kill the boss
  • Valenti decreases defense and attack of the enemy
  • Just unlocking Deathpierce’s unique ability will suffice
Warzone Glutton.png Attribute speed.png Cleanse debuff / Burst
  • Either burst the enemies with HP attribute heroes or use heroes that can cleanse to negate the boss' unique abilities
Overwhelming Terror.png Attribute hp.png Freeze
  • Continuously Freeze the boss to stack Red Hawk & Elizabeth's unique until you can one-shot the boss with her Ultimate
Vigorous Conqueror.png Attribute hp.png Deplete Ult & Increase Defense
  • Always deplete the ultimate move gauge or prevent it from filling up
  • Use heroes that can mitigate incoming damage (Red Dogedo)
Timespirit.png Attribute hp.png Disable Everything but Attack & Disable Ult
  • Red Slater’s skill Disables Everything but Attack skills.This is useful against the boss because it has no Attack-type cards.
  • Use Vivian’s skill to Disable Ultimate Move
Bishop of Love.png Attribute strength.png Disable Buff and Debuff
  • Blue Lilllia secures the rest of your team's HP
  • Blue Arthur is the main damage dealer
  • Blue Diane inflicts rupture damage
  • Blue Gowther at skill level 2 disables buff and debuff
Frenzied Giant.png Attribute strength.png Sustain
  • It is key to keep Blue Galland alive with your sustain
  • Heal using Red Elizabeth and provide additional HP using Blue Marmas
  • Red Elizabeth’s debuff can disable the boss from using attack skills
Explosive Giant.png Attribute strength.png Petrify
  • Rank up to petrify the boss
  • Only use an Ultimate when you can one-shot the boss
Illusion Amber.jpg Attribute speed.png Attribute hp.png
  • Counter with affinity advantage
Illusion Amber.jpg Attribute hp.png Attribute strength.png
  • Counter with affinity advantage
Illusion Amber.jpg Attribute strength.png Attribute speed.png
  • Counter with affinity advantage

Team Recommendations

Training Grotto Lv3 Teams

Resource Tips

  • Only use Hammers/Anvils/and Equipment Engraving Stones on your SSR equipment
  • Since Hammers are extremely rare to acquire, only use it when your equipment’s desired bonus stat is around 80% of its max value
Stat Value



2.4% or higher

Crit Damage


Crit Defense

Recovery Rate

Regeneration Rate

4.8% or higher
Crit Chance

Crit Resistance


3.6% or higher

Boss Information

Speed (Blue)

Hendrickson.png [Goddess Amber Illusion] Hendrickson
Obsessed Knight.png [Blue Amber] Obsessed Knight
Warzone Glutton.png [Blue Amber] Warzone Glutton

HP (Green)

Overwhelming Terror.png [Green Amber] Overwhelming Terror
Vigorous Conqueror.png [Green Amber] Vigorous Conqueror
Timespirit.png [Green Amber] Timespirit

Strength (Red)

Bishop of Love.png [Red Amber] Bishop of Love
Frenzied Giant.png [Red Amber] Frenzied Giant
Explosive Giant.png [Red Amber] Explosive Giant