space - Identify this story about cosmic entities please

This story was written long ago. It would be less than 250 pages. The story was about a cosmic entity not unlike a star, but these guys weren't stars or even black holes. They were conscious and mobile, and to be quite frank solar systems were just toys and playthings to be made, watched and then knocked apart when you got bored of them. The time frames in this story were on the order of 100's of millions of years per chapter in the life of this little fellow.

As this one cosmic entity got bored or disenchanted with the status quo of all cosmic life, he decided to take a trip across the void and left the realm of stars and galaxies, and spend billions of years just pushing forward until eventually he started to see the light of another realm ahead. He plunged headlong into this universe, and explored until he discovered a girl cosmic entity.

My synopsis of this story is absolutely horrid, but it's the best I can do from what I remember, and quite frankly the story was written pretty ambiguously anyway. If you can help identify this story for me, I would appreciate it.

Answer

This is almost certainly "Into the Darkness" written by Ross Rocklynne, initially published in Astonishing Stories in June of 1940, and collected elsewhere, as in The Golden Years of Science Fiction Volume 2, edited by Isaac Asimov.

The story is much as you describe, with the main character—a being named "Darkness"—being larger than star-size, and existing on a much longer time scale than human, who is capable of impelling himself around the universe. He eventually grows bored with playing with the other such beings by slinging planets around, and eventually sets out to cross a great void where he meets a female [Aside: interesting that male/female sex was imputed to creatures of such cosmic scale!], mates with her, and discovers that while females can breed thrice before dying, males can breed only once. His dying act is to disperse protoplasmic parts of himself to a small planet, third from the star, near a spiral galactic rim.