Trey has a sweet, friendly and gentle demeanor, unlike his brothers' cold and/or brutal nature. Trey loves his family a lot and doesn't want them to fight, attempting to mediate disputes between Quattro and Quinton. Dutiful and trusting, Vetrix stated that Trey always completed his missions, which are usually important.[6] Quinton also trusts Trey more than he does Quattro, due to Quattro's recklessness and hastiness.[7] Though concerned about his family's fate, he shows concern for Hart Tenjo during Vetrix's ritual.[8]

Although Trey is normally kind and slow-tempered, he can get serious if it is about Duels because he still wanted to Duel Shark, even after Vetrix told him to feel free to lose after he hands Shark "Number 32: Shark Drake".[6] His caring personality is also reflected through his Duels, within his Tag Duel with Quattro, he used his cards to not only protect himself, but Quattro as well.[9]

Trey also showed amazement towards Yuma Tsukumo for his protection to Kite Tenjo, and had developed an interest in him.[10][11] Trey has a strong interest in ancient history and in OOPArts, which seems to be rooted from the fact his father researched them. Trey was able to recognize all of Kazuma Tsukumo's ancient artifacts, in which he shows amazement.[5]

Armored III

Trey in armor.

When Trey eventually gains a portion of Vetrix's power, his personality hardens and bears a colder, more serious demeanor in his desire to meet his family's expectations, destroying many of his own beloved monsters, including his favorite card, just to reduce the ATK points of Yuma's monsters. Eventually, he broke Yuma's spirit and captured Astral using his crest and the powers that Vetrix gave him, as well as gaining an Roman-styled armor. He became cruel and sadistic just like his older brothers, even attacking a helpless Yuma and proceeded to laugh evilly when Yuma was hurt.[12] As the Duel continued, his powers continued to affect him and infuriate when he fails to succeed at something, even appearing to kill Astral and hurt Yuma's friends when both tried to interfere with the duel and prevent Yuma from losing. He would even go as far as to kill Yuma as he got angry when Yuma didn't fall to his death from the road and he even refused Yuma forfeiting and just skipped Yuma's turn so he could defeat Yuma immediately with his powers.[13]

At the end of his Duel with Yuma, Trey reverts back to his loyal and caring personality, having developed a true friendship with Yuma, and passes his hopes for his family to him.[14] Following Vetrix's reformation, Trey retains his peaceful demeanor, but has grown more confident and shown fierce protectiveness towards Yuma.[15][16] Trey has gained a penchant for mocking his enemies, when he replied to Mr. Heartland when he questioned the usefulness of his friendship with Yuma, claiming it could be used to "crush flies", referring to Mr. Heartland.[16] or after depriving Mizar of his "Number 107: Galaxy-Eyes Tachyon Dragon" and being the subject of the Emperor's disgust and anger, he simply replied he was "honored by the compliment".[17]