MMM 2014: Megaman V (Charged) Part 2

Well at least Megaman is almost done dealing with all of the Robot Masters wreaking havoc across the world, but Dr. Cossack has interrupted Megaman bringing him both good news and bad news. Thankfully, Megaman has almost all of the extra parts needed for Cossack to build Beat for him.

The bad news however is that Protoman has learned of Megaman's involvement and has taken those defeats personally. In fact, since he knew that Megaman would do so well against all those Robot Masters, he personally gave Megaman the coordinates to his secret fortress and challenged Megaman to go up against him.

Slowly but surely, the time will eventually come when Megaman must deal with his older brother. But why now all of a sudden? After going so far to save Kalinka from the clutches of Dr. Wily, why would Protoman suddenly wish to not only drive all the humans away, but to destroy Megaman? Why?