Disclaimer: This guide covers only the fights against the Demon King during Episode 548: Those Who Leave, Those Who Interfere and Episode 550: Father and Son.
Summary[]
The Demon King goes from one average Story boss to one of the most challenging bosses in the game and we have to fight him a total of 4 times (to date). Twice during Chapter 24 and twice during Chapter 25. It is in Chapter 25 where it gets more complex and what we’ll cover in this guide since it demands specific units in both fights. The Demon King shares some effects in both fights: he deals +200% damage to Goddesses (which makes any of those units completely nonviable since they will be lost after a couple of attacks), he will disable attack skills with his level 2 AOE attack, and he does more damage to debuffed enemies. As most Story bosses he’s immune to debuffs so it’s impossible to Encroach him which makes Blue Festival Berserk Estarossa not as useful as we would want him to be, although Darkness will still work since it’s a grey debuff and it can be stacked to its max.
Boss strategy (Episode 548)[]
The most important thing here is to go first at all costs to ensure you get the upper hand in terms of the number of attacks you have, but also it is better because you can place a taunt (if you have it available) and directly rush your Ultimate to end it in one single turn. This fight requires you to use a Ban variant character on your team. AVOID using either Demons or Goddesses in this fight since the Demon King will also deal +200% damage to Demon race units during this fight. A good choice can be Red Ragnarok Ban as your sub, this will make your team take less damage and deal even more damage in all your turns. Since the Demon King is a sole unit, he will be able to spam his Ultimate Move thanks to the continuous merge of his cards, so it is recommended to end this fight as soon as possible. A good setup is a full-Human composition, since it’s highly advised to not use Demons or Goddesses, Human units can provide a cheap and solid way of going around this fight, such as Blue “The One” Escanor or Red Excalibur Arthur. Other units you might use are units that only accept one debuff (such as Green Brunhild and Red Brunhild with her Holy Relic) to avoid stacking ignites if they get focused.
Best Teams[]
The best team compositions can include:
Tank[]
Red Excalibur Arthur: He can increase the damage dealt by every ally in battle if they’re all Humans. He also provides a lot of HP and a taunt which is much required during this fight. His Ultimate Move is also useful since the Demon King will most of the time have a lot of Ultimate Orbs.
Red Twigo: With his Holy Relic he can set a taunt since the start of the battle, even if you don’t go first his Taunt will take place and the Demon King will be forced to attack him. But be careful, since he’s an old unit (and also an R) he is really weak so make sure you have good gear for him to take all those attacks.
Utility[]
Red Kizuna: With her rank-ups on her skills she can increase all allies’ Attack-related stats and her second skill grants several buffs including Debuff Immunity which will make you unaffected by Demon King’s attack disable.
Green New King Arthur: His passive increases allies’ damage dealt by 35% and decreases their damage taken by 35%. This makes him a great option if you cannot go first since his passive works from the moment he steps on the battlefield, effectively reducing the damage you receive even further.
Red Slater: His passive decreases all enemies’ Crit Resistance by the value of Slater’s Crit Chance at the start of the battle. This helps a lot in making the Demon King take even more damage from your attacks.
Red Ragnarok Ban: Since a “Ban” named unit is required, Red Ragnarok Ban can be a viable option since he will decrease Demon King’s Pierce Rate, Crit Chance, and Crit Damage while increasing all of our Attack-related stats.
DPS[]
Light “The One” Ultimate Escanor: One of the best (if not the best) DPS at the moment in the game, his Ultimate can end the fight, and if he doesn’t get disabled one turn you can deal a lot of damage to the Demon King during that single turn. Also, Escanor becomes immune to any effects if he reaches 0 HP.
Blue “The One” Escanor: Even after the appearance of Light “The One” Ultimate Escanor, Blue “The One” proves to be still relevant in PVE content. He can provide himself with immunity after 3 turns and reach the peak of his power by increasing his stats several times with his passive while ignoring Demon King’s attack-disable move. A good strategy can be rushing your Ultimate and waiting until Turn 3 so you can attack the Demon King in that turn with all your Escanor cards. A high Ultimate Move level on Escanor can prove useful since Death will make your Ultimate do overall more damage.
Other Units:[]
Green Diane: Just like Twigo, she can place a Taunt even if you don’t go first since the battle starts, although she doesn’t provide the degree of the potential damage that Red Festival Queen Diane can deal.
Blue Brawler Ban: With a team including Fairy King Harlequin, and equipment with full Resistance Rolls on Ban (even R gear works but it must have the rolls in resistance), you can make the Demon King proc Patience on Ban, which will reduce his damage output by a 60% at max. Remember, Ban must NOT receive damage in order for his passive to keeps working so make sure you have always a Harlequin card to set up the barrier. Resistance Food and/or Resistance Artifact can help with this.
Blue Fairy King Harlequin: He’s integral for the Blue Brawler Ban strategy to work properly, his passive provides a barrier every time he attacks, this will ensure Ban doesn’t receive any damage and keep his passive working. Also, his Ultimate Move can help by dealing a lot of damage.
Boss Strategy (Episode 550)[]
Like in the previous fight with the Demon King it is recommended to go first. During this fight, we are required to use any variant of Meliodas. The Demon King will start this fight with 5 orbs in his Ultimate Move Gauge so at the second turn he will start using it. During this fight, it is also not recommended to use any Goddess unit since they will take more damage. Also, the enemy will heal 20% of the lost HP at the start of his turn and if he doesn’t receive any damage he will recover 50% of his Max HP so it’s recommended to end it in as few turns as possible. During this fight, it’s required to use a Meliodas which allows some degree of flexibility but the same kind of formation is recommended: a tank (or two) a utility unit, and a DPS, or even a tank or 2 DPS units.
Best teams[]
Ult rush also appears to be the best choice here since this time the Demon King can also disable your Attack skills. Going first is the best here but if you go second it can also work for you with the units listed.
Red Excalibur Arthur (or a full-Human formation) is only partially recommended here, it can work but only if you use Meliodas in the back, for which a specific version of Meliodas (Blue Champion Meliodas) proves to be the best. Any Meliodas can work as long as he’s present in the team, but for the sake of utility, this variant of Meliodas can provide the best support.
Tank[]
Red Festival Queen Diane: As the best tank in the game, she’s capable of soaking a huge amount of damage while also protecting her allies and making her attacks stronger the more damage she receives.
Red Twigo: Same as before, if you don’t go first and have his Holy Relic, he will place a Taunt for you to cover your units from receiving any single target attacks.
Green Diane: Same as Twigo, if you don’t go first she will set a Taunt and make your allies receive less damage. It's a less powerful taunt at the start but during your turn, you can set her Heavy Metal to Taunt the Demon King again and make her take most of the attacks.
Utility[]
Blue Champion Meliodas: This version of Meliodas can work in the Sub-slot, from where he can provide extra damage to his units thanks to his passive.
Green New King Arthur: Same as the previous fight, Green Arthur can provide a lot of damage while also increasing the defensive capabilities of our units.
Green Estarossa: Estarossa can be useful as a sub-slot character if you’re using Red Festival Queen Diane. He can provide her with Debuff Immunity when she uses her Stance, thus ignoring the attack-disable which will allow her to attack freely in the turn you decide to go all in. He can also go in the front since Demons no longer receive extra damage to deal damage with his Full Counter.
Green Merlin: Can help with her passive to accelerate an Ult Rush.
DPS[]
Dark Traitor Meliodas: One of the best DPS in the game, Meliodas can also grant a reduction in the damage your allies receive as long as he (or his allies) uses 2 or more skills. His Ultimate can be useful even without the Decrease All Stats effect since the Demon King is immune to all debuffs.
Blue “The One” Escanor: His Ultimate Move shines during this fight. Since the Demon King’s “Revive” passive gets activated after the damage calculation has ended, Death can kill him without triggering it even if the first hit doesn’t kill him, thus, making it a way to speedrun this fight.
Red Freyr: Just like Escanor, Freyr can do a lot of damage but he can provide some degree of utility by making your allies immune to Ignite which will reduce the damage output of the enemy. His Ultimate also has the Death effect so it also makes him a great asset for this fight even with the attribute disadvantage.
The Fairy King Harlequin-Brawler Ban strategy also works here but it will take more time to end the fight since the Demon King will pop his Revive passive and heal during each of his turns.
Make sure your Meliodas and Harlequin have high Ultimate Move levels so they can end the fight.