When it comes to an anime that shares a similar DNA to Trigun Stampede, then the easiest and most obvious answer is Kekkai Sensen, also known as Blood Blockade Battlefront. After all, both of them are created by the same author, Yasuhiro Nightow.

In Kekkai Sensen, the story takes place in a version of New York City that has been isolated from the rest of the world by a barrier. The main character, Leonardo Watch, is a young photographer with the ability to see supernatural beings. He joins an organization called "Libra," which fights against these supernatural threats. Leonardo is not a conventional hero, as he is often cowardly and hesitant to fight, but he has a strong sense of justice and a desire to protect his friends and the city.

Similarly, in Trigun Stampede, the main character Vash the Stampede is a skilled gunman and fighter, but he is also a pacifist who refuses to take a life. He often uses humor and wit to diffuse tense situations, and he has a unique and charismatic personality that draws others to him. Like Leonardo, Vash is not a typical action hero, but he has a strong sense of justice and a desire to protect others.

Both Kekkai Sensen and Trigun Stampede feature unconventional protagonists who are not your typical action heroes, but who are driven by a desire to do what is right and protect those they care about. They both also use humor and wit to add levity to what can be serious and intense situations.

While Deca-Dence and Trigun Stampede are very different anime series in terms of their setting, plot, and characters, one similarity between the two is that they both explore the themes of hope and the struggle to survive in a harsh and unforgiving world.

In Trigun Stampede, the world is a barren wasteland where violence and chaos rule, and the main character Vash the Stampede is a beacon of hope, trying to promote love and peace wherever he goes. Similarly, in Deca-Dence, the world is a post-apocalyptic wasteland where humanity struggles to survive against the Gadoll, and the main characters Natsume and Kaburagi fight to preserve hope and protect humanity.

Furthermore, both anime series also feature complex characters with their own unique struggles and motivations, who grow and change over the course of the story.

In No Guns Life, the story takes place in a world where some humans have been modified with cybernetic enhancements, and the main character Juzo Inui is one such person. Juzo is a "Resolver," a kind of private detective who takes on cases related to the extended cybernetic body modifications known as "Extendeds." Like Vash in Trigun Stampede, Juzo is a skilled fighter who uses his abilities to protect others and uphold justice, but he also has a troubled past and struggles with his own identity.

Similarly, in Trigun Stampede, the main character Vash is also a skilled gunman and fighter who travels a post-apocalyptic world while being pursued by dangerous enemies. Like Juzo in No Guns Life, Vash is also haunted by a troubled past and struggles to reconcile his actions with his desire to protect others and uphold justice.

Both No Guns Life and Trigun Stampede feature complex protagonists who are skilled fighters but who also struggle with their own inner demons and past traumas. They both also explore themes related to identity, justice, and the consequences of violence.

If what makes you interested in Trigun Stampede is its dark subject matter and heavy topics, then you’d like Ergo Proxy. Because both of them explore philosophical and existential themes related to the nature of humanity and the meaning of life.

In Ergo Proxy, the story takes place in a dystopian world where humans live in domed cities to protect themselves from a deadly virus. The main character, Re-L Mayer, is an investigator who uncovers a series of mysteries related to the nature of the city and the true nature of the virus. The anime explores themes of identity, consciousness, and the nature of reality, and raises questions about the meaning of life and the purpose of human existence.

Similarly, in Trigun Stampede, the main character Vash the Stampede struggles to reconcile his past and present and grapples with the question of whether violence and destruction are inherent in human nature. He also felt responsible for the atrocities caused by his brother’s action. Furthermore, the anime also explores themes of morality, redemption, and the struggle to find one's place in a chaotic world.

Both Ergo Proxy and Trigun Stampede are considered to be thought-provoking anime that challenge viewers to think deeply about the human condition and the nature of existence. While they differ in their approach to these themes, they share a similar desire to explore the deeper questions of life and what it means to be human.

It goes without saying that Wolf's Rain and Trigun Stampede are quite different in terms of their setting, characters, and themes. However, one similarity between the two is that they both explore the concept of the search for a better life or a better world.

In Wolf's Rain, the story takes place in a post-apocalyptic world where wolves have been hunted to extinction. However, a group of wolves who can disguise themselves as humans embark on a quest to find the legendary "Paradise," a place where they believe they will find a better life. The anime explores themes of hope, survival, and the search for a better world, as the characters face numerous challenges and obstacles on their journey.

Trigun Stampede takes this concept and turns it to eleven by pitting the two twin brothers against each other. Because both Vash and Nai try to find their own version of “a better world”. To Vash, it is a world where everybody can live happily in harmony. On the other hand, Nai believes that the source of all the bad things in this world is human beings. Therefore, “a better world” is a world without human beings in it. A world that is solely populated by Plants. The whole series is basically about the clash between these two contrasting ideologies.

At first glance, there seems to be nothing similar about Attack on Titan and Trigun Stampede. After all, one is a story about a human that can turn into a giant that fights against other giants, while the other one is about a happy-go-lucky gunman who can shoot through everything. But once you peel the layers and look deeper into both stories, then you’ll begin to see some similarities.

In the final season of Attack on Titan, the story of Eren and his friends not only gets darker, but it also becomes much more complex. You see the length that Eren would go to in order to exact his vengeance, and you’ll also see the centuries of abuse that the Marleyan have caused to the Eldian people. At that point, it’s hard to point your finger at who is actually the good and the bad guy in the story. Both have justifiable reasons behind their action, and both fight to the death in order to protect their own people.

Although it might not be as complex as Attack on Titan, a similar thing also happens in Trigun Stampede. As mentioned above, Nai’s dream is basically to create an utopia for his people, and he sees human beings as the entity that constantly abused his people. He sees how little humanity cares about the well-being of the Plants, despite the fact that they are absolutely relying on the Plants. So in his mind, the only way for his people to prosper is to get rid of the source of their problem. Vash may be opposed to how Nai goes about achieving his dream, but even the peace-loving Vash can’t deny the atrocities that humanity has committed to his people. He is just willing to give them another chance, which is not something that Nai would do.

So in a sense, both series focus on the conflict between two opposing forces that simply want to create a better place for their people. If that is the part of Trigun Stampede that you like, then you’ll find this particular theme being explored even more deeply in the final season of Attack on Titan.