The “vow of renouncement” is one of the defining points of conflict in the story of Attack on Titan. It is essentially a limiter placed on the Founding Titan’s powers. Regardless, it makes for some interesting discussions on morals in the anime and manga itself. Therefore, it’s only fitting that it is explored in-depth once again!

How did the vow renouncing war come to be?

The 145th Fritz King was tired of the violence that his ancestors had brought upon the world. The Great Titan War was the final straw, and he wished for peace and the betterment of those oppressed by the Eldian Empire. Therefore, when he planned on bringing an end to it by shifting as many Eldians as he could to Paradis with himself, he also tweaked the powers of the Founding Titan so that it can never be used for war again. We have covered the Great Titan War in a different article; click the link to read more about it!

What does the vow do?

Due to this vow, the Founding Titan would never interfere if Paradis were to ever be attacked. This is because the king believed that if the race was destroyed, it would be atoning for the crimes their ancestors had committed. Furthermore, this vow can overwrite the strongest of wills. For example, Uri Reiss along with Rodd Reiss did not agree with their father’s ideology. However, when Uri became the Founding Titan, this disagreement vanished and he preached what his father did in his time.

Similarly, the vow also burdens the royal inheritor with the past which presumably is what makes them preach about “atonement”. Frieda Reiss seems to be distraught once she inherited the Founding Titan; which hints at just how difficult this vow was on the inheritor. Subsequently, we see Frieda argue with Grisha over this exact same thing when he confronts the Reiss family.

Another condition of the vow is that the full powers of the Founding Titan can now only be unleashed by those of royal blood. This is why Eren seems to not be effected by the vow or use the Founding Titan for anything, relying on his Attack Titan for combat.

The overturning of the vow

As mentioned above, the Founding Titan is redundant with a nonroyal inheritor. However, Eren manages to overturn the vow and unleash its powers twice. These two events then help Eren hypothesise a theory to break free from the Founder’s vow. This theory is backed up by Zeke later on.

Eren comes in contact with Dina Fritz

Injured and abandoned, Eren and Mikasa are at the brink of death when he suddenly punches the smiling titan. This is the same titan that not only ate his mother but Hannes. At that point, something triggers the mindless and intelligent titans. Turns out, the mindless titans seem to understand Eren’s intention- to get Reiner. They immediately start to attack Reiner to stop him from getting close.

Even when Reiner does manage to fight them a little, Eren screams “get away from me!”. The mindless titans keep ambushing Reiner and Bertholdt because they took Eren’s words as an order.

Once Eren inherits the memories of his father, he finds out the identity of the titan. It is Dina Fritz, a royal from the continent and the first of wife of Grisha, and mother of Zeke. Therefore, when Eren touched a royal blooded titan, he managed to briefly use the powers of the Founding Titan for attacking.

Eren kisses Historia’s hand

At the award ceremony after the conclusion of the retaking of Wall Maria, Eren kisses Historia’s hand as a courtesy. The second he kisses her hand, it triggers memories of his father. This again showed us that royal blood is important for Eren to master the founding titan. However, we realise that contact with a royal blooded titan yields stronger result than just contacting a royal non-shifter.

Zeke Jeager’s suggestion

When Zeke and the Survey Corps finally establish connections via the volunteers, he introduces to them a way to get the Founding Titan to work. As seen in the case of Dina, Zeke wants to meet Eren, or to be more precise, he needed a royal blooded Titan shifter to come in contact with a founding titan without royal blood. By doing so, they could access the full powers of the Founding Titan without the vow’s activation. Since Paradis was in a tight situation, this was an extremely crucial event to happen for its survival.

It is important to again stress why this is necessary. The vow’s activation would inevitably bring the downfall of the island.

Here’s a little more detail on why the vow became invalid;

The only person who can order around Ymir is the founding titan with royal blood. There are two conditions that need to be met, one needs to possess the Founding titan and also needs to have royal blood. Eren only had the founding titan, he never was able to reach the paths by his own volition. Same with Zeke, he couldn’t voluntarily go to the paths whenever he wanted or order around Ymir (he did meet Ymir when he was about to die, but that was not voluntarily).

But, when Eren and Zeke came in contact, both the pre-requisites were met. There was a titan with royal blood and there was also a Founding Titan, meaning they could finally access the paths and unlock the full powers of the Founding Titan. The key was found. The vow was no longer binding the Founding Titan’s holder.

TL;DR

After the conclusion of the Great Titan War, the 145th King created the “vow of renouncement”. This vow restricts the Founding Titan by two ways. Firstly, it locks away the powers of the Founding Titan when it is not with someone of royal blood. Secondly, it makes the titan useless in times of danger as it wants to maintain “peace” (accepting Paradis’ extermination).

Eren manages to overcome the vow by coming in contact with a royal blooded shifter. The meeting of the Jeager brothers becomes an important event later in the story because of this; they need to meet so that they could unleash the Founding Titan’s powers to bring an end to the conflict.