Boss battles are important in Seven Deadly Sins if you want to limit break your heroes. Normal and Easy Bosses are generally easy to deal with but, the real challenge comes when you try to do Extreme. This guide will help you complete the Extreme Boss easily!
In order to beat the Gray Demon on Extreme mode you’re going to need a team of DPS, Buffer, and Support. Green Skinny King is one of the best heroes to bring for DPS.
Team Composition
The team composition is going to consist of DPS and Utility units. Since the Gray Demon has Speed attribute and is weak to the Fairy race, it is best to bring Green Fairy units. Gray Demon cannot be stunned or CC’d so the strategy used in Red Demon does not work here. If you need some help with Red Demon, check here for our Extreme Red Demon Guide.
DPS
 Green Skinny King | Green King is the best possible hero to bring in the Gray Demon raid due to his Skills, Unique, and Race. He has massive damage while at max ultimate orbs and is your main DPS. |
 Green Meliodas | If you cannot bring Green King then the next best option would be Green Meliodas. What makes him a lackluster is his 2nd skill, Counter. Since the Gray Demon cannot be hit by Physical attacks while flying, your only option of damage is his first Skill. |
Utility/Support
 Green Helbram | This hero will be used for buffing up your allies and removing the enemies buffs. Helbram raises all Attack related stats which means, Attack, Crit Chance, Crit Damage. |
 Green Gilthunder | This is another good hero that is used for buffing Attack stats. Gilthunder only raises the Attack stat of allies but can be stacked and used with Helbram’s buff. |
 Green SSR Elizabeth | This hero is a great healer and has an ultimate which can give your allies Ultimate Orbs. Since Green King gets more Crit Chance the more orbs he has, this is very useful. |
*Since you can stack Helbram and Gilthunder attack buff, it is best to coordinate with a friend and you each bring one.
Substitute Slot
 Green Cain | Cain is possibly the best hero to have in the sub slot for any Raid Boss run. He has a Unique skill that increases all allies Attack-related stats by 10% in a Death Match. The downside is that he will require you to spend a lot of SR Pendants in order to UR him and get his Unique skill. |
 Green Alioni | If you need a budget version of Cain, you can use Alioni. He will require a ton of R Pendants but, you don’t really need them anyway. He only increases HP attribute allies’ Attack-related stats by 10%. So if your hero isn’t Green, it will not get buffed. |
Alternatives
In the future when Gowther comes out, he will be a must have on your team. His Skill allows him to raise the rank of your allies Skills which is extremely useful.
Blue King can also be used for his heals and damage. Since he is a Fairy he will do bonus damage but only use Blue King when you can’t use Green King.
Example Teams
So ideally, this is what your team will look like.
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Your allies team should look like,
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In the future, the 3rd slot can be played around with and will depend on who you have that’s stronger. Since this is just an ideal setup of what you want, it isn’t the only setup that can clear it.
Other teams that work,
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I’ve seen situations where only one person had Green King and it worked fine. The more you stray from the ideal, the higher the chance of failure.
Step By Step
First thing you should do is to get your total co-op CC over 180,000. This way you’ll be able to attack first.
When you enter the match the first card to use is the buff card. Both you and your ally will buff and then you proceed to use your attack cards. On the next turn, you should decide whether or not you need heals and continue attacking. If you get your ULT on the first heart, save it for the next heart.
Once you are done with the first heart you’ll notice a Green Bar underneath the HP of the Gray Demon. The Green Bar, if taken down, will stun the Gray Demon. The cards you should use at the start of the second heart are, Buff, Helbram ULT, and 1 King ULT. The rest of the cards should be attack cards. Remember to use King Attack cards before you King ULT to get max damage. The Helbram ULT is to get rid of the HP buff that the Gray Demon will have.
After that turn, he should be stunned. Once stunned unleash your other King ULT and other damage cards. By this step, Extreme Gray Demon should be down and completed.
If you prefer visuals, check out our video: Extreme Gray Demon Guide!