As we know, Shanks sacrificed his arm for the New Age. But what if there is an even deeper reason for this?
In chapter 1138, Shamrock says that Shanks returned to Mary Geoise, but that he left to continue being a pirate. At this point, we can deduce that Shanks must have started some training with his father Figarland Garling, when he was leader of the God's Knights.
In chapter 1140, we saw two more God's Knights being summoned through the pentagram.
It is said that to cross the pentagram one must have the mark. In other words, it is a mark that all God's Knights have.
If we look more closely at Saint Summers' body, we can notice that he has a mark on his left arm that curiously resembles the summoning pentagram. It's the only part of his exposed body that we can see a mark on.
The same goes for Gunko, as Oda made a point of drawing her without pants, to show that there are no marks on the lower part of her body.
We can infer there is a pattern: all God's Knights have this mark on their left arm, including the Five Elders. Since we never see their arm uncovered, we can imagine this is the case.
Shanks sacrificed his left arm in chapter 1. We never see Shanks's left arm uncovered, which means there may have been this mark there.
If Shanks had the mark on his left arm, it means he completely abdicated his celestial roots, recognizing the sovereignty of the next Joyboy.

In chapter 1138, Shamrock says that Shanks returned to Mary Geoise, but that he left to continue being a pirate. At this point, we can deduce that Shanks must have started some training with his father Figarland Garling, when he was leader of the God's Knights.

In chapter 1140, we saw two more God's Knights being summoned through the pentagram.

It is said that to cross the pentagram one must have the mark. In other words, it is a mark that all God's Knights have.

If we look more closely at Saint Summers' body, we can notice that he has a mark on his left arm that curiously resembles the summoning pentagram. It's the only part of his exposed body that we can see a mark on.

The same goes for Gunko, as Oda made a point of drawing her without pants, to show that there are no marks on the lower part of her body.

We can infer there is a pattern: all God's Knights have this mark on their left arm, including the Five Elders. Since we never see their arm uncovered, we can imagine this is the case.

Shanks sacrificed his left arm in chapter 1. We never see Shanks's left arm uncovered, which means there may have been this mark there.

If Shanks had the mark on his left arm, it means he completely abdicated his celestial roots, recognizing the sovereignty of the next Joyboy.
