I started this right after I posted Luigi. I struggled quite a bit through this. My vision isn't great to say the least.

Bowser's story,

Thousands of years ago there were many kingdoms. All of which had royalty, kings, queens, princesses and princes. These kingdoms were imbued with magical energy. As the royalty were the centers of power they were the most magically charged. As these kingdoms grew so did their enemies. An ancient race of dragons lived deep within the earth would come to realize that the consumption of the people of these kingdoms would grant them power and longer life. The dragons, being very few, slowly began to kidnap the citizens and consume them. Their power grew steadily but in small increments. The tribe leaders of the dragons felt that to rule and to do so forever that they would have to consume more citizens. One of the tribal leaders, against the judgement of the others tribe heads, felt that this process would result in too slow an ascendency. He toke it upon himself to strike at the heart of the magic, the royalty. Specifically the sons and daughters. He gathered his few allies and took several kingdoms by surprise. His power grew rapidly enabling him to strike more distant kingdoms. The other tribe's power waned in their reluctance to follow this mad lizard and as a result were too eaten and absorbed.

As the centuries passed Bowser's grip on the land grew until there were only two princesses left. Daisy and Peach. With almost no allies left in their world they reached out to ours. Enlisting Mario and Luigi. As these two plumbing heroes chased Bowser from castle to castle they realized that there was ancient ritual that needed to be conducted in order for the magic to be consumed properly. This ritual had to be precise or it would fail. Which is why each time Mario and Luigi would arrive at a castle's dungeon only to find that the princess had been whisked away moments before to another castle. Their only advantage was the interruption of the ancient ritual. Bowser, who was only two princesses away from total power, ended the chase by confronting the two Italian men. Ending the life of one and sending the other away defeated. He retreated to the ancient caves within his world taking the princesses with him. Word of their fate has not been heard nor discovered.

For Luigi's story [link]