Attack on Titan is a Japanese manga series written and illustrated by Hajime Isayama. The story revolves around a boy Eren Yeager (male protagonist) who lives in the town of Shiganshina.
In the year 845, one of the three walls was breached by two new and different titans, The Colossal Titan and the Armored Titans.
We saw that during the incident Eren’s mother was eaten by a titan which traumatized Eren to a very large extent.
Here we do have a lot of questions about Eren and his family. Like why Eren didn't like his father and why did he try to manipulate him?
What was the bond between the two brothers?
Why did Eren eat Grisha?

It is shown in the very first season of the manga that Eren meets his father and was really happy about it but why did he eat him?
This happened when his father decided to give his power to Eren. Though in the process Eren becomes a pure titan and eats up his dad hence, as he took all the power he had held.
Grisha defeated Freida Reiss and took control of the Founding Titan, and killed each member of her family except Rod Reiss who escaped.
After this, he is successfully shown to inject a serum kind of thing into Eren who turns into a Titan and kills him.
This part of the manga series was disclosed in the third season of the anime and it is marked and said to be the most important and viewed part of the show, as this episode gave the fans of the manga a view of what will happen ahead.
Eren and Zeke Yeager
Eren and Zeke are brothers. Zeke first learned about Eren when Bertolt and Reiner came from their mission and got to know that Eren was born from his father’s second family.

Although they first met as enemies during the battle of Shiganshina District.
Though with time we saw that he trusted Zeke enough to turn against his friend at the survey corps and plot with him an attack on Marley.
Zeke appreciated having a younger brother with whom he can be honest and relate.
Also, Pieck also noticed that the encounter between Zeke and his brother was the last time he saw Zeke being honest.