I'm going to do what every spoiler set does, and start with the landmark card from the set: Mega Man.
So here he is, the blue bomber. Why is he not blue, you ask? Well, despite the color of his outfit, Mega Man's characteristics are all white, all the time. He fights for order and justice, and attacks evil wherever he can find it. Straight white, all the way.
I had several iterations of this card before I settled on this one. Flavor-wise, here's what I was thinking. When Mega Man dies, he starts at the beginning of the level. Hence the "on top of the library" portion. The second part (which I call Smiting Hero, because of Smite and Intrepid Hero) is basically just to emphasize how strong Mega Man is. Any enemy who challenges him falls. Finally, the last part is the truest Mega Man flavor. He grows stronger as he defeats enemies. The +1/+1 counter effect could've been limited to just when Mega Man uses his ability, but that would take out the times when he simply defeats a creature in combat. While it might seem a little inelegant, I felt this was the best way to capture the situations I was looking for.
In my next spoiler, I'll highlight the two masterminds behind the set. My guess is you can bet who they are.