Episode 12 of TRIGUN STAMPEDE is definitely one of the best episodes of the 2023 Winter anime season for various reasons, including its amazing conclusion of the series' dramatic depiction of the bond and eventual conflict between Vash The Stampede and his older brother, Millions Knives. During this climactic final episode, TRIGUN STAMPEDE sets up its sequel series, while also fleshing out the reasons for the majority of the series' deviations from the original look and feel of the series, and in the fight between Vash and Knives, the series shows a sliver of Vash The Stampede's original character design.
This final episode ties together some loose ends, while presenting new questions from the aftermath of the battle between the siblings, solidifying the true purpose of TRIGUN STAMPEDE: to retell the original series while also serving as a prelude; possibly to a Trigun much more familiar to fans of the original series, but hugely different from its predecessors. How does a call-back to Vash's original design support TRIGUN STAMPEDE and its return to self?
Choir of Angels
In the final episode of TRIGUN STAMPEDE, Knives has long begun his thorough deletion of Vash's memories in an attempt to recreate him alongside a legion of Independent Plants borne from the forced surrogacy of the countless Plants Knives amassed from his journey across No Man's Land. However, due to help from Meryl and the resilience of Vash's emotions for his adoptive mother, Vash is able to break free from the synchronization with Knives and the other Plants, and therefore closes the interdimensional gate that Knives was using in order to enact his plan.
With Knives ejected from the network he'd created, Vash and his ability to resonate with their kind effectively granted him the power of countless Plants, all condensed into a single cube of unfathomable energy. To access the higher dimension once more, Knives needs this energy source, but Vash tries his best to keep it out of his brother's grasp. During a desperate attempt to keep Knives at bay, Vash instinctively forces this power source together with his gun, which then forces Vash's Angel Arm, an ability that he should have lost after his conflict with Knives as teenagers, to materialize in a form it has never assumed before – angelic, as the Plants appear, but dark. The symbolism throughout the series has positioned Vash and Knives on opposite ends; biologically and ideologically, as an extension of the well-known myth of the Dioscuri, or the Gemini.
Windswept
As Vash's Angel Arm manifests in its full capacity, Knives attempts to use the ability to lay waste to every single human living on No Man's Land, so Vash strives to have the weapon fire off into space, keeping people out of harm's way. The manifestation of Vash's true powers also comes with a major physical change: instead of bright red, Vash's jacket is darkened, assuming a purplish colour related to the ominous rays of light that emanate from the Angel Arm; and Vash's hair stands on end in the way that it would throughout his depiction in the initial stages of the Trigun 1998 anime and the original manga. In the 1998 series, hair was another aspect in which the contrast between the brothers was highlighted. Initially, Knives and Vash had their hair grow to be extremely long, so Rem offered to cut their hair.
Knives, already developing into the individual who'd eventually kill everyone, decides that he wants to define himself and decides to give himself a haircut. On the other hand, Vash's original windswept hair is supposedly reminiscent of Rem Saverem's lover named Alex, who had a similar style, and this windswept Vash is what we get for the majority of his final battle with Millions Knives. The call-back to the original design of Vash The Stampede was one of various elements in the TRIGUN STAMPEDE story used to first create the foundation of the story before allowing it to grow into itself – the Trigun that fans are familiar with. In a sense, seeing Vash come back from having his entire self nearly erased to confronting his brother looking like his original design is the series confirming that it hadn't gotten rid of some of its most popular elements, but was merely warming up to them.
Aftermath
Unfortunately, Knives's desire to "return everything to even" ends up getting him vapourized in the immensely powerful beam fired from the "Angelic Choir" version of the Angel Arm ability. Not only does Knives die, but Vash's idea of having the weapon fire off into space doesn't account for the impact of Vash crash-landing back on the surface of the planet with a condensed energy source created from the distillation of the energy of countless Plants all firing off at once.
This causes the destruction of July City, and led to the true and complete vilification of Vash The Stampede in the eyes of society. This incident, "Lost July" is effectively the ground zero of the Trigun narrative as it was in the original anime and manga, and most fans will be familiar with a Trigun that already knows July to be lost. However, serving as a retelling and prelude, TRIGUN STAMPEDE's inclusion of Vash's windswept look in the final battle which led to this "ground zero" incident in the narrative, points towards a TRIGUN STAMPEDE that has fully justified its deviations from the original story through working towards those aspects through the story itself, as seen with the episode teasing at the return of Milly.