The Training Grotto, also called the Training Dungeon, was introduced to the global version of Seven Deadly Sins: Grand Cross in June 2020. The Japan/Korea version of this feature was previously called the Training Cave. In the Training Grotto, you can acquire materials used for strengthening equipment as well as Amber Keys to draw equipment by battling against the Goddess Ambers.
This page is intended to be a basic overview of the Training Grotto to get you started. Additional team recommendations are available on this in-depth guide for even more assistance in ensuring you make the most of your time in the Training Grotto.
Contents
Training Grotto Overview
Entering the Training Grotto
To gain entry to the Training Grotto, you need to begin by spending a key.
As of the 03/08/2022 update, keys no longer replenish automatically. The Training Grotto unlocks on a weekly basis every Monday at 12:00AM PDT. The Training Grotto will be closed every Sunday from 11:00 PM - 11:59 PM PDT.
After you use a key, 30 Ambers are placed when the Training Grotto opens, of which five are selected at random as Ambers that can be battled against. These five will appear on the bottom of your screen.
Once each Amber has been defeated, the Amber will disappear and one of the remaining Ambers will be selected to become available for battle. Training ends and the Training Grotto closes once nine Amber battles have been won.
Once this happens, you cannot enter the Grotto again until you receive a new key. A completion bar on the right side of the screen shows your progress towards finishing your current training session. Training Grotto Keys will be used to reset the content, but they do not affect how much remaining time is left prior to the Training Grotto closing again.
Battling in the Training Grotto
The most important thing to remember about the Training Grotto is that each hero can only enter battle once! Heroes who have participated in battle may not be set to the team again. Thus, to optimize your chances of finishing the training, ensure that you strategically position your heroes to ensure you can clear enough Goddess Ambers. It is also important to note that Equipment stats do not apply to heroes while in the Training Grotto.
There are currently four levels of Ambers:
- Level 1 - Enemy CC 60k
- Level 2 - Enemy CC 75k
- Level 3 - Enemy CC 90k
- Level 4 - Enemy CC 120k
An Illusion Amber will appear after every three Goddess Ambers cleared, regardless of their difficulty levels. Rare rewards such as Equipment Engraving Stones can be acquired from these Illusion Ambers. Completing Ambers of higher difficulties will cause the gauge to fill even faster. Definitely don’t miss your chance to battle an Illusion Amber!
Training Grotto Rewards
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 | 
|
Upgrade Equipment to UR |
| Hammer of Vaizel | 
|
Randomly increases the value of bonus stats |
| Anvil | 
|
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.
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.
- Complete missions to unlock maximum rewards. Each of the links below shows the missions that relate to each boss and its Ambers. Complete all 5 missions for a given Amber to obtain the maximum amount of rewards.
- In order to use Auto Clear, a level must be cleared with 5 stars and your account's Combat Class must be 20% higher than your enemy's Combat Class.
