Battle-born—this is a term used in modern-day Earth for individuals who have an exceedingly high intellect for battle.
Even without any training, they would be able to hold their own against experienced veterans. They are led by their instincts that guide them towards the path of victory, and it was mainly this type of people that could easily enter the state of flow during battle.
And this was what Spark was. Not only did he have a concerning mental condition that caused him to have murderous impulses, he was also battle-born—a human who was basically fashioned for killing.
Talk about giving wings to a tiger.
Back then, when his foster father discovered all this, he didn't get mad or scared. He took his time and made sure he sculpted Spark, directing him to walk the right path.
And through rigorous training, Spark had fully mastered the art of entering the state of flow—which he just did now.