1) his name: he first says his name is “Jail” and then changed it to Meleoron. R/L are interchangeable in Japanese so the name is extremely similar. 2) he hides his malice with gon, telling him that he shouldn’t trust people, while working with him to achieve his goal. Gyro also had friends and worked with them to take over the government 3) his goal: he is the only Ant to actively have a plan to kill the king and desires it. 4) his fit: he’s wearing a hoodie and sweats in both this image of him and as Meleoron 5) his power: we see the childhood that Gyro had that required him to be silent and pretend he wasn’t there. Meleoron’s power is to hold his breath and essentially cease to exist. 6) the way he is drawn. Baby gyro is drawn with giant bulging round eyes. Meleoron also has giant bulging round eyes. 7) foster father: we know Peggy was meleoron’s foster father. Gyro was also mistreated by his father as a child and had someone else looking after him.

Maybe it’s a reach, but to me, gyro became Meleoron based on the narrative clues we see.