I thought this was common knowledge, but the more I discuss Marco these days the more I see how half the people have no clue how his power works.

So let’s break it down.

1) Marco’s regeneration has a limit.

This was confirmed by Oda in a SBS.

Question: Hello for the first time, Oda-sensei. I’ve read all the previous 57 volumes, and I was thinking, I don’t quite understand how “Phoenix Marco”‘s Zoan fruit of the “legendary beast” kind is different from Ace’s “Meramera” fruit. P.N. CNY

Oda: Yeah, I know… I’ve omitted the explanation from this war arc, because I focused on the pacing and wanted to move the story forward. To explain Marco’s ability just a little bit: he’s Zoan, so he does have a body. But since he’s got “the blue fire of revival” – the Phoenix’s ability – wounds will regenerate, so attacks will not damage him (though there’s a limit to the regeneration). In other words, the flames are for regeneration. These blue flames don’t have the characteristics of actual fire – they don’t spread and burn things, and they aren’t hot. They’re completely different from Ace’s flames. I might touch on this in the main story at some point, so I’ll leave it at this for now.The limit can also be shown by the fact that after MF during WB’s funeral Marco was wearing bandages, implying he had at least some injuries he could not heal with his powers because they had run out at that point.

2) Forget limbs, as long as his regeneration is available Marco can survive mortal wounds.

Example #1 – Kizaru turns him into a swiss cheese, and blews off a part of his brain.

Example #2 – A fodder puts a sword through his skull.

Example #3 – Queen almost detaches his head from the rest of his body.

The panel should be self explanatory. This is why Marco can basically stall anyone, including Admirals and Yonko. There isn’t much more that you can do when mortally wounding a guy doesn’t work. There’s only two ways to deal with him:

– Remove his regeneration with seastone (like in Marineford) or with some hax powers (for example turning him into a toy with Sugar’s power)– Keep wounding him so he needs to regen until he reaches his limit and can finally be killed (pretty much the standard strategy)

It’s not clear if you could simply knock him unconscious (like Luffy after Thunder Bagua) or if his regen would kick in and wake him up immediately [Remeber that Enel jump started his heart…] but considering that even Big Mom didn’t wanna try and wanted to move on I’d go for a no.

3) Is it really impossible to kill him while he has his regen?

Okay, there might be a way. In DBZ, the way to kill Majin Bu is to simply wipe him out completely. Wipe out every atom of his body so that there is nothing that can start the regeneration process.

This might work, or maybe not because maybe Marco would regenerate even out of thin air, who knows. But the point is moot because there is no one who has shown the attack power to do anything close to that. Maybe a magma bath from Akainu could do that, but I doubt that it would be quick enough to kill Marco before his regen kicks in if Marco has freedom of movement.

So at the end of the day, as long as his regeneration is available Marco is basically immortal.

*Theory by Patryipe