Sin Dragons & Key Heroes Overview – July 5th, 2021


The Sin Dragons & Key Heroes event returns to North America and features one of the worst possible designed REMs to date. This is because the event cards are mixed in with the regular, non-GFE REM which means rolling a first evolution Pantheon card will happen far too often. Furthermore, most of the buffs/love this time around went into the 7-star rarity who all feature abysmal rolling rates. To top it off, players cannot Monster Exchange for any card along several of the 6-star cards being valuable.

To make matters worse, many of these cards no longer keep abreast with newer options which in turn makes it harder to justify rolling. Thankfully, all players will receive a total of 30 free rolls over the duration of the event. As such, I would not spend Magic Stones to roll until after all 30 freebies have been acquired as you may not need to roll any more afterwards.

With that being said, I will be continuing my shorter format articles due to my wrist pains in order to shed some light on what we can expect from this event.

Video commentary


Sin Dragons & Key Heroes REM Pros & Cons – July 2021
  • All cards have a Weapon Assist
  • 30 free rolls for all players
  • Several powerful/unique cards at 6/7* rarity
  • No Monster Exchange
  • Terrible rolling rates
    • 50% rolls will be non-Event cards
    • 6% for 7*
    • 18% for 6*
  • Most cards have not aged well
  • Skippable event due to underwhelming odds
    • Especially if you rolled before
  • Bottom rarity cards (5*) have lost their edge
Sin Dragons & Key Heroes REM
7 Star base
(6% total)
6 Star base
(18% total)
5 Star base
(26% total)

Icons show Base form/form they come out in

Sin Dragons & Key Heroes – July 2021

Order within each tier is random and not reflective of ranking

Bottom rarity quick summary

The bottom rarity should be the main motivation to roll in an event and the following chart shows all the 5-star Rankings. In total, they comprise 26% of the rolling pool.

This 26% is misleading as 50% of the pool is non-event cards. This means only 24% chance for any 6/7* card.

Sin Dragons & Key Heroes Bottom Rarity (5*) REM Rankings – July 2021

7 Star base

All of the 7-star cards have significant value in at least one of their forms but the 6% total rolling rate is quite abysmal and will often lead to sadness.

Miya (New) – S

  • 3 SB Skill Boost & SBR Skill Lock Resist in Base form
    • Base form also has 50% Shield per leader
  • 2 turn CD post-Transform
    • Unlocks board
    • Generates 5 Light & Hearts
  • Outstanding leader skill
    • Huge Damage Reduction
      • 2 components
      • Can always activate via active
    • +2 combos with 2 light Combos
    • Significant ATK multiplier
    • 9x RCV to easily heal up to full HP
  • Huge personal damage
    • Massive ATK stat
  • 3 Team HP & L Shield
  • No Auto Follow Up Attack
  • No VDP
    • Wastes all personal damage vs Voids
  • Hard to roll
    • A bad event to roll in
    • 1% chance
    • No Monster Exchange
  • Light is missing several JP-exclusive cards
    • May make it harder to team build
  • Next wave of Powercreep is soon for Flowers

Miya is a wonderfully powerful leader but she is featured in a terrible REM from a rolling point of view while also not being available via the Monster Exchange. Furthermore, NA is lacking several notable Light subs which will make it harder to team build. To make maters worse, the next big wave of Powercreep via the Flowers will come soon (date unknown, but soon) which will be a better place to roll as the SDKH event has aged poorly relatively speaking.

With that being said, Miya is pretty amazing overall as she has immense bulk, outstanding personal damage, easy activation through self-System, and should have the potential to clear all content. Just be mindful of the fact that she lacks VDP and will have to rely on other cards to solve these encounters.

Miya’s 2 turn cooldown ensures she can always activate her Leader Skill and the tremendous Damage Reduction will enable her to survive even the most punishing attacks and can be further bolsterd by her L Shield awakening.

Gileon – A

  • 3 SB Skill Boost & SBR Skill Lock Resist in Base form
  • High Effective HP if above 50% HP
  • Valuable active post-Transform
    • Board changer
    • RCV & TE buff
  • High personal damage
    • 45 45 45 45
  • 27 turns to Transform is still too long
    • Comparing him to other Transforming cards
  • Loses significant Damage Reduction when below 50% HP
    • Vulnerable to multi-hits
  • No bonus combos
  • No Auto Follow Up
  • Requires a Healing Solution
  • No VDP
    • Wastes all personal damage vs Voids
  • Guard Break feels wasted

Gileon looks impressive on paper with his additional buff but it still does not address his main problems: no RCV multiplier, no bonus combos, no Auto Follow Up Attack. Furthermore, his Damage Reduction drastically lowers when falling below 50% HP and comparing him to other current leaders, he does not keep abreast.

3 Fire combos for additional Damage Reduction is challenging to achieve and goes against his original playstyle of using Rows Fire Row and Combo Orbs and with 6×5, it may be challenging to achieve. As such, 7×6 Swapping may be helpful but you cannot use a Transforming card as the Swap.

Finally, a lack of VDP hinders team building compared to Seina or Tanjiro as this type of damage may be difficult to fully address with double Gileon.

As a sub, Gileon can be useful but his 27 turn Transformation feels too long.


  • Full Cleric active
    • Clears all Binds/Awoken Binds/Unmatchable
    • Board changer
    • Full HP Heal
  • 2 Team HP
  • SB Skill Boost
  • 2 Enhanced Orbs Enhnaced Fire Orb
  • Hard to roll
  • Board changer does not produce Hearts
    • Also makes Jammers

Gileon’s Weapon is able to provide a Full Cleric active along with tri-elemental Board Changer on a respectable 12 turn cooldown. This can be an option for players who lack the stronger Full Cleric options but even if you do not use the active on this Weapon Assist, it will still be valuable as 2 Team HP and a Skill Boost Skill Boost will always be meaningful.

Menuit (Weapon) – S

  • SB Skill Boost
  • Team HP
  • 2 Team RCV
  • Invaluable active
    • 2 turn Damage Absorb Void
    • 2 turn Attribute Absorb Void
    • 2 turn Void Damage Void
  • Hard to roll
  • Overlaps with Boar Helmet
    • Boar gives no RCV but more HP
  • Less suitable for dungeons with multiple spawns spaced out

Menuit’s Weapon grants one Team HP and two Team RCV awakenings along with a single Skill Boost Skill Boost. Just this alone is meaningful but this Weapon also comes with an outrageously powerful active skill.

This active will provide 2 turns of Damage Absorb Void, Attribute Absorb Void, and Void Damage Void on a 23 turn cooldown. At least one of these will be needed in a given dungeon and having all 3 greatly eases team building while also providing bulk and enhanced recovery.

Amly (Weapon) – A

  • SB Skill Boost
  • +2s orb movement time
  • Unique active
    • 2x TE buff
    • Board Unlock
    • 1 Spinner for 1 turn
      • Greatly aids orb generation for any team
    • 5 turn CD
  • Highly situational Weapon overall
    • Ideally counter Spinners or less unique

Amly’s Weapon is quite unique as it offers a 5 cooldown active that generates a Spinner along with a Board Unlock and 2x TE buff. This helps ensure any team can “fish” out whatever colours are needed for activation.

Naturally, this works best when Spinners need to be countered but the easy orb generation should not be overlooked.

In her Transforming form, Amly features a 2 turn cooldown that generates 2 Spinners for 2 turns. This can be abused like Mikage to always fish out orbs you require but success with this hinges on how much Time Extends you have on the team.

Ferule – S

  • 3 SB Skill Boost & SBR Skill Lock Resist in Base form
  • Fantastic post-Transform active
    • 3x ATK
    • Row of Light
    • Locks Light
      • Soft counter to  Spinners
  • Significantly improved LS
    • Immune to Poison damage
    • Flat HP & RCV for Light
    • Unconditional ATK multiplier
      • Do not have to match any pattern
    • Bonus combos & Damage Reduction with 6+ Light orbs matched
  • Ferule System is a little bonkers
    • Adjusted 1200x ATK multiplier
    • +6 Light orbs every turn
    • +4 combos
  • Powerful Light sub
    • Like Grandis but with -3 CD to Transform
  • 27 turns to Transform is still too long
    • Comparing them to other Transforming cards
  • Full System requires 2 Ferules plus Friend
    • Systems also have less active skill diversity
    • Active does not generate Hearts & may remove them
  • Damage Reduction tied to 6 Light orbs
    • Offset by System
  • Personal damage is lower without VDP
    • 45 45
      • Offset by 3x ATK buff
  • No Auto Follow Up Attack

Ferule has received arguably the best buff for the original 5 due to the fact that they can fully activate their ATK multiplier by just existing along with a much needed Damage Reduction component.

Ferule’s 2/20/2 aspect is unconditional for Light cards which greatly eases constraints and the additional 35% damage Reduction (and +2 combos) per leader when matching 6 Light orbs turns her into quite a powerful leader. Furthermore, with a Ferule System (2 leads, 1 sub), players will enjoy a constant stream of +6 Light orbs and 3x ATK which raises the effective ATK multiplier to 1,200x every turn.

This in turn grants easier clears with minimal effort and she should have no issues handling WoC2/SR2 or below with a well crafted team. Just be mindful that Ferule lacks Auto Follow Up and her active skill may remove Heart orbs.

As a sub, Ferule can function wonderfully well on mono-Light teams and her reliable orb generation and ATK buff will always be helpful.


  • SB Skill Boost
  • SFUA
  • Combo Orb
  • Interesting active
    • Unlock
    • 15 Light & Heal orbs
    • 50% Shield for 2 turns
    • 3x ATK for 2 turns
  • Awakenings are kind of mish-mash
    • Hard to take advantage of all
  • Opportunity cost of not using Ferule System

Ferule’s Weapon feels a little awkward due to the highly situational awakenings. If you are able to take advantage of them, this Weapon can have meaningful impact but the opportunity cost of not using their Transforming form is too high at this point.

Euchs – S

  • 3 SB Skill Boost & SBR Skill Lock Resist in Base form
  • Fantastic personal damage when <50% HP
  • Huge ATK multiplier + Auto Follow Up
  • Can form a Euchs System
    • 2 leads, 1 sub
      • +6 Dark orbs
      • 35% Damage Reduction
  • 27 turns to Transform is still too long
    • Comparing him to other Transforming cards
  • LS Shield all tied to being below 50% HP
    • Healing over often results in death
  • Requires far too much juggling/effort compared to other leaders
  • Only truly shines with System
  • Somewhat capped at SR1 difficulty
    • Juggling HP becomes incredibly hard
    • Stalling is problematic

Euchs is still a dominant leader for SR1 due to the Tank and Spank nature of the dungeon. What I mean by this is that SR1 includes relatively few mechanics and instead features durable spawns who hit reasonably hard.

As such, Euchs excels in this environment as they have enough Effective HP to tank every thing along with outstanding damage output. This is further facilitated by a Euchs System as you can then use one every turn to produce +6 Dark orbs and 35% Damage Reduction.

While all of this looks promising, juggling your HP is a hassle compared to how mindless other options are (eg. Tanjiro ) along with not being able to truly tackle harder content due to the fact that healing over 50% HP will result in certain death in SR2/3 along with their actual Effective HP not being as high when their shield only works below half health.


  • Skill Boost SB
  • <50%
    • Becomes relevant in hard content when being hit continuously puts you <50% HP
      • 2x ATK for owning card
  • 2 Dark Rows Dark row
  • Valuable active
    • Generates a row of Dark
    • 2 turn Damage & Attribute Absorb Void
    • 15 turn CD
      • Exceptionally low due to 50% HP cut
  • Fantastic Weapon for mono Dark farming
  • Optimal for Dark teams
  • Adds no bulk
    • Comparing to Boar & Menuit

Euch’s Weapon is wonderfully powerful as it provides a Skill Boost Skill Boost and <50% awakenings along with 2 Dark Rows Dark row. Universally speaking, the Skill Boost will always have merits and the <50% still brings value for a wider variety of teams, especially if pushing through challenging content.

This is because end game content often features large, unavoidable, repeated hits which can leave players below half health on a regular basis. As such, the owning card will enjoy 2x personal damage while also carrying a valuable active.

This active is naturally best for mono Dark, but the 2 turns of Damage and Attribute Absorb Void is quite spicy along with the shorter 15 turn cooldown due to the 50% HP cut. While this is quite powerful, it does have significant overlap with other 2 turn Absorb Void options (Boar and Menuit ) while also not providing any bulk. This lack of bulk may be an issue when trying to reach key HP thresholds which in turn may sideline it.

On the other hand, this Weapon is incredibly powerful for mono Dark farming set ups as essentially every aspect brings value.

As a whole, I feel this will be Euch’s best form at this point in time due to his niche/edge of being a speedy and brainless SR1 leader having less merits due to more easy to use teams.

Wrath – S

  • 4 SB Skill Boost
  • Solid personal damage
    • 45 45
  • Valuable SA
    • or
  • Strong active
    • 3x ATK buff
    • Full Bind/Awoken Bind clear
  • Covers Red for SR3
  • Fantastic sub
  • Does not clear Unmatchable
    • Have to rely on other actives
    • Longish cooldown
  • Difficult to roll

Wrath is still my favourite Sin Dragon due to his ability to provide Skill Boosts Skill Boost, reliable personal damage, L , and a valuable active. In fact, I almost always include him on my mono Dark teams as his kit is difficult to replicate.

This active will clear all Bind and Awoken Binds along with a 3x ATK buff. Sadly, he cannot clear Unmatchable which will be his largest downfall as players must rely on a different active to solve this mechanic. This is most problematic in newer content but Wrath can still function as a reliable solution for Binds/Awoken Binds.

Greed – S

  • 3 Dungeon Bonus
    • 1 of 2 cards in NA to have this
    • Greatly aids solo farming
  • 2 SB Skill Boost
  • 14 turn CD
    • Harder to inherit over

Greed’s entire value revolves around their 3 Dungeon Bonus awakenings which increases the drop rates when playing Solo mode. This has most notable applications when farming for Event Medals, Coins, or even just bolstering Rank EXP from Experience of a Lifetime.

For Event Medal farming, Dungeon Bonuses increase the chance for something to drop from a given floor, it has no impact on the rarity of drops, just the quantity. What this means is that players will be able to play a lower difficulty (usually Int.) in solo mode to save stamina and ability to Button through the dungeon. This saves time and mental sanity while also being quite lucrative.

Greed is unique and nearly irreplaceable from a Dungeon Bonus point of view and having a couple of duplicates is still valuable.


The Sin Dragons and Key Heroes feature wonderfully powerful cards at the top rarity but the event as a whole is plagued by terrible rolling rates, no Monster Exchange, and 50% of the rolls being non-event cards.

This creates little motivation to roll in this event, especially if you have done so in the past as the buffs only truly helped the top rarity which only comprises a tiny fraction of the rolling pool. On the bright side, all players will enjoy 30 free rolls in this event which may satisfy any urge to roll.

With that being said, let me know what you think about this event in the comment down below.

Happy Puzzling!

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4 thoughts on “Sin Dragons & Key Heroes Overview – July 5th, 2021”

  1. Thanks for the reivew the focused style is great, particularly for all the top heavy machines we have been getting recently.


  2. Thanks for the review. I honestly enjoy this more condensed style of writing, I think it makes it easier to get to the most relevant information.


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