The villain of Mobile Suit Gundam Wing is not a distinct character; instead, it is the very idea and glorification of war. As specific characters embody this idea more than others, they rise as vessels for the concept of war while remaining unique presences with a few understandable motivations or admirable characteristics. Treize Khushrenada's passion for war and chivalrous manner, combined with his prodigal knowledge and talents, therefore made him a significant entity in Gundam Wing.
Off the bat, Zechs Merquise seems poised to become the lead antagonist of the series, as he is quickly paired and contrasted with the lead protagonist Heero. Zechs also resembles the most iconic villain in Mobile Suit Gundam history -- Char Aznable -- which implies his importance as an opposing force for the heroic characters. Zechs plays an incredible antagonistic role by clashing with the Gundam pilots and Relena both on and off the battlefield. However, in the end, Zechs' mentor Treize plays the most powerful adversarial role through his impact on the characters and embodiment of core themes.
Acting as an impressively manipulative and charismatic force throughout Gundam Wing, Treize moves almost every character like a chess piece toward his goal of bettering humanity's future. As one of the finest examples of the ends not justifying the means, Treize believes that society will find itself stronger and better if it embraces the necessity of warfare as a mechanism of defining its path to a brighter future. He enters the stage as a well-refined and confident individual who has helped mold multiple individuals into soldiers through his charismatic and convincing nature.
Almost every key younger member of OZ is inspired or saved by Treize, earning him a level of loyalty that stems from genuine respect and admiration. He quickly noticed the potential in Lucrezia Noin and Zechs and brought them into his inner circle. Guiding Noin and Zechs as soldiers while inspiring influential minds like Lady Une and Dorothy Catalonia allows Treize's influence to bleed into all facets of the conflict between Earth and the Space Colonies.
Through charm and charisma, Treize wins the loyalty of civilians, and through his battle acumen and Mobile Suit designs, he wins over the soldiers. To be such a charismatic leader at such a young age speaks to Treize's true strengths. While he may be a masterful tactician, top-notch fencer and brilliant Mobile Suit designer, his natural skills lie in drumming up people's emotions and devotion.
Treize's impact and charisma penetrate so deep into people's core beliefs that they begin to create fanatics or extreme loyalists. For example, lady Une, an ambitious and intellectual member of OZ, falls entirely in line with Treize's war rhetoric, so much so that her mental state begins to shatter when he chastises her actions. As a result, she later develops a split personality that opposes the vehement warmongering that once defined her whole being.
While the influence on OZ and other like-minded individuals is apparent, Treize also significantly impacts the protagonists, namely Wufei and Heero. Wufei's commitment to his cause and trauma from experiences in the warring world builds him into Treize's main rival in the series. Treize and Wufei believe in specific codes of conduct and hold firm to their beliefs. Their characters and opposing views develop them into respectful opponents whose stories keep intersecting until the end of the series.
Heero and Treize find more common ground due to Heero finding peace and reassurance in his nature through Treize's philosophy on war and a soldier's duty. Treize's development of the Epyon Mobile Suit and its predictive system helps Heero and Zechs further see their roles in Gundam Wing's endless war. The mutual admiration between Treize and specific Gundam pilots reveals how impressively charismatic and talented the tyrannical Treize truly is.
By profoundly affecting both sides of an enormous war, Treize helps numerous people find themselves and their places in the world. His passion and intellect give weight to beliefs that humanity needs war and bloodshed to evolve, even if those beliefs are crass and twisted. Rarely does a supporting character profoundly impact the whole cast, whether directly or indirectly. An impactful and charismatic tyrant can drive a story into deeper themes and emotions that it may never have seen without such a magnetic villain.