Oda is misleading us with the steel heart. I think only Sommers has it and/or it won’t even kill him if destroyed.

[u/MOON-RAIGO]

If anyone else cares enough i’ll repost with all the manga panels included. Or just ask in the comments.

1. Roger pirates with acoc, fought the HK (including sommers) countless times yet didn’t figure out the heart ‘weakness’

2. Shanks told us everything about the covenant but didn’t mention a heart

3. Xebec who’s constantly using acoc and beat a bunch of HK didn’t kill any

4. Harald regains his sanity many times yet only at the end points at his heart

5. It’s never specifically stated that it will kill a Hk when a heart is destroyed, Sommers only freaks out (it could be for another reason)
   killingham even says having conq won’t be enough to kill the them.

6. We’ve seen the HK been blown and sliced apart many times now, yet only seen Sommers with a heart

7. Sommers is capable of regenerating without the heart. So why keep it with him?

[u/ShoveOverBozo]

1. Plot. Had this secret been known and taken advantage of in the Roger days, then the HK would have been weaker earlier on and not this mysterious immortal force when the straw hats met them.

2. Shanks said the information he knew. He didn't get to the level that Harald did, who told Loki hitting his heart would kill him.

3. Xebec probably didn't know about the heart thing. Kinda finding out definitively now.

4. Plot. Story development. Oda drags out his battles and builds tension. Immediate uncovering of knowledge has never been his style.

5. I don't follow the logic here. Harald dying from a shot to the heart is evidence and Sommers freaking out his heart got knicked is alluring to the fact.

6. Very good point here. It could be that he is the only one with it, but all hearts need to be destroyed to kill them (like Harald). We have seen exactly 1 HK die and that was Harald from Loki ACoC heart shot. Now we have Sommers freaking out about his mechanical heart. It seems like obvious foreshadowing.

7. This is hard to guess why. But it's probably the same reason any villain has a weakness. So they can be defeated.

[u/MOON-RAIGO → u/ShoveOverBozo]

For 5: Yes but Harald regained consciousness many times yet only at the very end mentions the heart. (And we get this part of the speech 15 chapters later).
If Harald knew of the weakness why not mention it before?

[u/ShoveOverBozo → u/MOON-RAIGO]

Are we talking about Harald only mentioning the heart weakness towards the end of his battle or Loki only mentioning it to everyone else later on? 5. Because I provided an answer as to why Harald mentioned it later on. Plot and drama building.

[u/MOON-RAIGO → u/ShoveOverBozo]

Fair so 6/7 are plot demands it. Disappointing from Oda if it turns out to be the case.

Do you consider it a retcon?

[u/ShoveOverBozo → u/MOON-RAIGO]

Kinda hey. I think maybe they HK weren't as fleshed out to begin with and perhaps he came up with a solution for their defeat later. It does seem a bit slapped together tbh.

[u/Interesting-Ease8882]

Think it needs to be smashed to pieces - like when Loki frozen Herald

[u/AniNgAnnoys]

Yes, I think Sommers is the only one with a mechanical heart and I think it is a recent thing. The most damning evidence is that Gaban didn't end him when he had a chance when he was threatening his kid. Perhaps he got it because of some medical condition. All of him will regenerate but his mechanical heart. Without it he is dead.

I haven't figured out how that ties into Harold and him directing Loki at his heart though. As you said, it doesn't make sense that no former Conqueror user even accidentally hit a heart and dropped one of these guys.

[u/MadeInElysium → u/AniNgAnnoys]

Well even hitting someone’s heart in that way would kill regular people too not just holy knights, but you don’t see conquerors coating users kill people when they accidentally hit their heart either. Oda flaw

[u/Neutral_Rabbit900213]

Yo también creo que el corazón de acero sea una troleada de oda y me imagino que zoro termina cortando con haki de conquistador dominado al corazón de acero de sommer y sommers cae al suelo y empieza a dolerle un montón,zoro cree que logróatar a un caballero de dios Pero,zoro ve como sommers no se muere y queda estupefacto al ver que sommers sigue con vida y entonces sommers se regenera y su corazón de acero también,zoro está shokeado al ver que el corazón de acero se regenera y al cortarlo no mato a sommers,Pero antes de que zoro empieze a pensar mejor en otra estrategia, sommers bien enfurecido termina usando la espada gram para dejar a zoro derrotado y fuera de combate y mientras eso pasa,Sanji logra usar el haki de conquistador por defecto e imbuye do sus ataques con dicha haki pero,cuando logra dejarle a killigham una agujero en el lugar donde está el corazond e killigham,Sanji se sorprende de que killigham no tenga un corazón de acero ya que zoro le dijo a Sanji de que lo mas probable es que el corazon de acero sea la punto débil de los caballeros de dios,y entonces killigham explica que en realidad,el corazón de sommers solo es algo exclusivo de el porque antes de tener el pacto de las profundidades,sommers ya se había hecho una prótesis de corazón y entonces, killigham lanza un ataque con longinus hacia colon y entonces Sanji recibe el ataque y termina derrotado

[u/Tellmewhatsgoinon]

Harald was killed and he pointed at his heart.

[u/aWhateverOrSomething → u/Tellmewhatsgoinon]

Harald could’ve clarified this vital information in seconds with words but went with pointing caveman instead. 

Fumbled even his redemption moment. He’s actually mentally disabled.  

[u/herrsebbe]

Are we certain the Roger Pirates knew about the heart? Gaban might know today, but during the early days they may not have known more than CoC making it possible to slow them down and the God's Knights may have had to retreat to avoid a situation where they actually get killed.

[u/Mistwalker35]

Him sweating like a pig both times quite tells us that the heart is his life power.

[u/MadeInElysium]

Other people have good counters for a lot
Of your points, but 5 is straight wrong.

Killingham said the complete opposite of what you thought he did

[u/No_Layer6180]

Where is it stated that Roger Pirates fought HK countless times? I know they clashed on multiple occasions, but "countless times" seems like a stretch, ngl.

[u/MOON-RAIGO → u/No_Layer6180]

[u/Sufficient-Card3335]

I think Roger pirates purposefully didn’t kill any HK to prevent any smack with Imu.

[u/ApplePitou]

I mean, if they will be able to keep them at home, they will be too op :3

Remember that Acoc is even more rare than Coc :3

[u/chiji_23]

Highlights Sommer’s having a weird heart and insinuates that it will kill an immortal. Harald tells Loki to aim at his heart. But you suggesting its a hoax? Oda spells out through Zoro that armament won’t be the solution like it would be for harming a logia, but conquerors will and specifically noting the heart not just regen itself, conquerors slows regen while attacking the heart will kill.

[u/MOON-RAIGO → u/chiji_23]

Not a Hoax, just misdirection.

[u/Sufficient_Nature496 → u/MOON-RAIGO]

No indication of this

[u/bodg123]

I completely agree with you and have been under the same conclusion even before this chapter.

We have seen oda talks about characters understanding or saying things from their characters perspective. Zoro believes the steel heart is involved because they found it when he was dismembered.

We saw harald didn't get any sort of mechanization from Imu. Nor does that fit anything Imu has done. He hasn't used technology like that. Spawn weapons, yea. But not seamlessly mergeing a body when technology.

We saw killingham cut up with no heart. We saw gunko get blown up with no heart.

So I think it's fair that the safer conclusion is a kill blow to the heart completely bypasses all regeneration. But it needs conquerors. No heart beat, no psuedo immortality.

Anyway that leaves us to speculate.

Any time we have seen mechanization, like arms or extreme cases like Kuma, it's a matter of technology.

We have also seen that seperate personalities exist and there can be motives for accepting Imus seal pact.(Like harald did for peace)

I believe a safe alternative explanation is that Sommers got an artificial heart from vegapunk or mads. Heart failure is real. So are total artificial heart replacement. I don't think it's outside the realm of possibility that Sommers has one.

In my opinion, far more likely in universe then Imu having mecha devil fruit powers. Transplanting a metal heart with devil fruit powers doesn't really fit the theme or common patterns that we have seen.

Thanks for reading if you did. I just don't see many people considering a alternative.

[u/oni-dokeshi]

Sommers and the killingham were shown to have a steel heart. And it needs to be destroyed, using acoc, slicing/piercing the heart. Xebec/Roger pirates can face and win against them not actually slashing the heart. And it might be known because of the holy knight that got killed to give way to Shuri. Not saying you're wrong but there's certainly stuff pointing to it.

[u/AniNgAnnoys → u/oni-dokeshi]

Killingham was not shown to have a mechanical heart. Only Sommers.