Suggested by Destroyer Optimus Prime is the most iconic Transformer of them all and he is definitely a tough fighter who won’t go down easily. He still won’t be able to defeat Gon though. Gon has his final mode which has enough strength and speed to easily take the edge over Prime. His Nen will be able to block Prime’s attacks but that’s assuming that any attack is fast enough to hit him. Gon’s edge here is considerable. Gon wins.