The Federation and the Empire, these two intelligent civilizations that accidentally encountered each other in the universe and immediately started a mode of war, each has a recognized strongest individual combatant.
In an era where interstellar wars can be initiated, the strength of individual combatants actually doesn't hold much significance. Even when combined with Mechas, or weaponry like the Xinghe, individuals who can dominate on the ground or in the vacuum of space, both sides have ways to avoid battle or neutralize such threats.
For example, Ji Xinghe now can disregard the Empire's four Space Fleets in space, but what else can he do besides disregard them? Initiating an attack is impossible, let alone winning the battle. Even if Emperor Wu III does not deploy that spacecraft from the third civilization, he cannot resolve the Empire's fleet, which has sixty main battleship-class space warships.
