Where/Who is the Original Super Saiyan God?

During the Battle of Gods movie Shenron explained that a Super Saiyan God had existed before, but there was none at that time. The original Super Saiyan God was believed to of been summoned by 5 righteous-hearted Saiyans would come together to put their power into another Saiyan to give that Saiyan the power of Super Saiyan God.

But, this power would only last for so long. The original summon was to help the Saiyan race fend against a bunch of evil Saiyans. This Saiyan lost due to the fact the power had ran out.

After this Saiyan lost, he presumably disappeared. What if he never left at all but instead became the Guardian of Planet Vegeta.

I understand some of you would question this as he didn't defend his home against Frieza but maybe he turned against his own kind after seeing what evil beings the Saiyans had become.

The Saiyans are indeed a powerful race and the Super Saiyan God could of became a legend due to the fact that they never needed to use this power again and it got to a point that when they needed it the most, against Frieza destroying their home, that they didn't have that kind of power anymore to defend themselves.

There are countless possibilities as what could of happened to the original Super Saiyan God like the one i just spoke about that the Saiyan could of became the guardian of planet Vegeta.

I believe the original Super Saiyan God could be on another planet protecting another race to become better than his own.

If anyone else has anything to add on, comment and thanks for reading.