Was there ever a reason for Lobo? Or better question is how was he I guess created to become invincible to an extent?

He is a Czarnian, a very rare alien species (for a long time he was thought to be the only one left) and simply naturally has his powers.

If I remember correctly had some wacky power scaling, he went to toe to toe with Superman in one comic and was much weaker in others, sort of all over the map depending on what the story called for

He was created as a sort of satire of wolverine. So the basic power set scaled off of that, and has gotten crazier over the years.

Originally, in his first appearance, he was just a bounty hunter. His partner Bedlam only appeared a few more times.

Be aware, his original costume was REALLY stupid.

Omega Men #3: