Shingeki no Kyojin Season 3

What's the truth of the world? The protagonists in both the series seek the answer to this question. The worldbuilding in these 2 series is unimaginably excellent. These 2 series take place in a world full of secrets and lies. They focus on supernatural mysteries and are deep and highly logical. There are lot of revelations that might leave you shocked. They share a similar eerie and dark atmosphere. It's interesting to see characters make deductions. SNK s3 is waaay better than its prequels. Music is exceptionally excellent. Art and background scenery is awesome. There will be interesting theories and philosophies. 

Note: There's a number of spoilers for Shingeki no Kyojin in this review, so if you haven't already finished SnK Season 3, I recommend you ignore this recommendation. Vinland Saga and Shingeki no Kyojin may look like different stories from the outside-SnK is a post-apocalyptic series set in a world where the last surviving humans hide behind massive walls from giant humanoid monsters called "Titans", while Vinland Saga is just about some Viking guy who wants to kill somebody, set in medieval times. But there's more to it than what meets the eye. Thorfinn is like Eren. A lighthearted little boy lives a happy life with his family in a small, peaceful communities (Shiganshina/Iceland). Their parents aren't very important (or so it seems) and both boys are happy with where they are. Two friends (Armin/Leif Erikson) both love telling stories about lands far away (in SnK's case, the world beyond the walls, in Vinland Saga, Vinland). This all changes when a stranger shows up and takes everything from the protagonist. Titans break through the walls of Shiganshina, devouring Eren's mother in front of his eyes. A voyage to Norway is cut short when Vikings attack the ship belonging to the protagonist's father; Thorfinn is held hostage while he watches his father get shot down by arrows. This is the hero's call to action. Eren vows not to rest until every single Titan is hunted down and killed. Thorfinn vows to kill Askellad, the Viking captain who murdered his father. Both stories have a similar theme at their core: Revenge. While Eren in SnK acts more level-headed and preoccupies himself with other tasks while still pursuing his main goal, Vinland Saga strips out the covering and lays the theme bare. Thorfinn agrees to join Askellad's army and prove himself on the battlefield as a warrior, so he can one day duel Askellad, and kill him. Thorfinn doesn't have any friends whatsoever- Eren has dozens. Thorfinn doesn't care about the politics of the world, he makes it clear his only goal here is to kill Askellad and that he's just been roped into the political climate by circumstances alone. Eren is much more respectful to the political system and doesn't have a problem with authority. Both Thorfinn and Eren have a harsh mentor figure: Askellad and Levi respectively. Askellad is more unlikeable than Levi, but is just as skilled. Levi has a dark past, and so does Askellad- but the latter's is much deeper and marked by sharp trauma. We also have Vinland Saga's Historia : Prince Cnut of Denmark. He's a boy with a personality like Armin's and Krista's, but he's much more timid and is afraid to even speak in front of other people, usually cowering behind his caretaker since childhood, Ragnar. Cnut has long, feminine hair and is often mistaken as a girl. He starts out as a figure similar to Krista Lenz, but just as Krista matures as Historia, so does he. Another similarity with Historia is that he's of royal blood. His personality is rather similar to that of Krista and Armin, but although a close companion of Thorfinn, the two aren't friends exactly. As I said, Thorfinn has one goal and one goal alone: Destroy Askellad . He could care less about some royal family. There are other characters with parallels to SnK Season 3 characters: Bjorn (Ervin/Hange) Thorkell (Kenny) Atli/Togrim (Berthold/Reiner) and so on. The main difference between the two is that SnK Season 3 is a story about plot and mystery, Vinland Saga is a story about characters. But this doesn't mean there's a big change in quality. The two have a very similar idea at heart, and if you liked one you will enjoy the other. read more 

Both shows have characters you can enjoy, both shows have coup d'etats. Both shows focus on Military and Politics, both shows have good animation, both shows have fight scenes, and both shows are addicting and have a very enjoyable plot. 

Both feature an island which had been ruling the world with its extraordinary powers and its war titans for centuries until it found itself in inner conflicts which spared the world from its dominance. The main heroine is a girl who is, unknowingly, a descendant of the island's royal family (a family that was split after the fall of the island) who grew up on a farm as a little girl. Together with the help of the male protagonist, she now has to decide over the future of the island's powers. Not to mention, the start of the Ending song "Akatsuki no Requiem" literally sounds like a Ghibli soundtrack, namely "A Town With An Ocean View".  read more 

These 2 are sequels to a series which have developed a deep mystery, but did not reveal a lot of answers. Finally, the answers are revealed (even if bot all in SNK s3 but a lot more than its prequels). There are too many secrets. I found them totally mind-blowing. It's interesting to see the characters make deductions and strategies. You might come to know that there were hints in the prequel but you missed them or things you thought to be less important turn out to be a key to solving the mystery.