The String Theory

At the beginning there was no matter as we know it, just the four elementary particles called: Electromagneton, Weak force, Strong force and Graviton. 

They lived together and regardless of their names they all had the same power. 

They knew their goal in life was to create life; but they hated each other because everyone wanted to be the leader, but no one could do anything to be stronger than his brothers. So to avoid quarrels, Graviton, the youngest of the four, decided to escape and broke the link that kept their brothers together, what he didn't know is that if one of the particles is missing all the power they enclose would be released in the strongest explosion ever: The Big Bang. 

The huge explosion occurred and the amount of energy generated separated the brother particles away and changed the Universe's laws.

As this happened Graviton felt he did bad, all seemed to be chaos! 

So he decided to fix the situation by looking for his siblings and bringing them together again. Everything would return to normality, he thought. 

The first one he found was the oldest: Electromagneton. Graviton asked for his oldest brother's help to look for the rest, but Electromagneton refused giving him any help. Then without his brother's permission, the youngest particle fused to Electromagneton's body and some how managed to go and look for the rest. This first union was enough to bring the other particles back and they all fused as well. This new union carried the configuration for creating life and that was how it happened. Despite what they were creating was beautiful they still did not want to be together but it was too late. 

As they were dissatisfied with the new fusion they decided to punish who they thought was guilty: Graviton. The three brothers punished his youngest one by sending him to another dimension so he could not try to make a different fusion again.

Graviton was confined to another dimension and as the time passed he wanted to find a way to make his brothers knew he was somehow close to them, so he grew up and gained enough power to start mixing dimensions and created what we know nowadays as gravity.