Competitive

It would be disgraceful for him to deny the convenience of his breakthrough. Things could have unfolded much worse if Ieyasu did not exist. Considering that his family very well may have been saved by Ieyasu helping Rui breakthrough so early, Rui decided not to pursue that line of argument.

He was being weirdly childish, in hindsight. 

They both were. A debate about who was superior where they tried flexing on the other was uncharacteristic of both.

Rui did not enjoy bragging about his superiority to other Martial Artists. He couldn't but feel like a jerk picking on the weak when he did that. In general, he disliked demeaning others due to their lack of talent compared to his spectacular growth.

But with Ieyasu, something was just a little different. He was on par with Rui, so a competitive spirit that Rui had almost never experienced before welled up.

'...When was the last time I felt that competitive?' Rui couldn't help but wonder.