A young man who keeps to himself most times, Viktor is determined and headstrong when it comes to accomplishing his goals. Growing up in the Undercity, he knows what it's like to be poor while having to fend for yourself, thus he's sympathetic towards the people of Zaun, taking offense when Jayce says they're dangerous. Although reserved and introverted, he's also idealistic and selfless, genuinely wanting his research and inventions at Hextech to improve the lives of both Zaun and Piltover citizens alike. Viktor also has comedic moments such as when he and Jayce went to sneak into Heimerdinger's lab and are found by Mel. He immediately tries to lie and humorously play it off by acting like he thought he was taking Jayce to his bedroom, showing he might not be the best at lying. Even though his intentions are pure, he can be hasty at times as he wanted Hextech to go out as soon as possibile despite the risks of it not being stable enough. This hastiness is partially understandable however due to the fact Viktor's illness is causing his lifespan to be cut short and he's afraid he won't able to put his research into effect while he's still alive. Although this expeditious attitude has paid off to some extent, it's also lead to some serious consequences and regrets. When Viktor recklessly augmented himself with the Hex Core while he didn't have any more shimmer, it almost consumed him and ended up costing him Sky Young's life when she tried to save him. This event left him devastated and almost made him destroy the Hex Core out of anger, but couldn't bring himself to do it.After waking up from his coma, Viktor appears to be more detached and emotionless than he was before, speaking to Jayce with even less energy and enthusiasm than he used to. Despite this, he still has a selfless attitude and the urge to help others as seen when he wanders around Zaun and looks at the people suffering, using his newfound powers to help cure Shimmer addicts. Viktor would later start a cult-like sanctuary where he would cure anyone who came to him for help, even though he knows doing so would diminish both his lifespan and powers every time he used them. When Singed comes and proposes to Viktor the idea of using Vander's blood to help stabilize him, Viktor refuses as he still values other people over his own life and ambitions. This mindset would soon change however after Jayce shoots him in the chest with his hammer, almost killing him. This event would cause him to think that human emotions are the reason why people suffer. With this new mindset, he would go on to evolve with help from Singed, completely changing his appearance and seemingly removing his emotions. He would then try and force this "Glorious Evolution" on the rest of humankind so they could all be of one mind, stripping away their individual free will. Despite his plans and emotionless demeanor, Viktor wasn't motivated to do any of this because of malice or evilness. He still believed he was doing the best thing for humankind as he thought they wouldn't suffer if his plan succeeded. However, his eyes are opened after Jayce reaches his human side and shows him the error of his ways, talking him out of his plan, thus reverting him back to the old Viktor.

"I understand now. The message hidden within the pattern. The reason for our failures in the commune. The Doctor was right -- it's inescapable. Humanity. Our very essence. Our emotions... Rage. Compassion. Hate. Two sides of the same coin, inextricably bound. That which inspires us to our greatest good... is also the cause of our greatest evil."