What science fiction saga has species at war over different kinds of stars?

Question

I'm having a hard time finding the name of a science fiction saga (I think the work spanned several books) that I read about a year ago on Wikipedia. Despite furious googling I have not been able to hit the correct story. I remember some plot points from a synopsis, and they are listed below. The following may contain spoilers.

• There are several intelligent civilizations, one of them human.
• There are at least two civilizations scoring really high on the Kardashev scale. Both of these species inhabit stars and are at war because one species needs red dwarfs and the other black holes or something similar.
• One of these mega-species is also at war with the humans, and their battles and tactics include time travel.
• The economy of the human civilization relies largely on the war effort, and at some point the ending of the war bankrupts Earth.
• EDIT: Additional fact came to mind: One of the mega-species might have evolved only moments after the big bang, making it ancient.

Do any of these plot points ring a bell?

Answer 1

I'm pretty sure it's the the Xeelee Sequence, by Stephen Baxter (see also here).

There are several intelligent civilizations, one of them human

There are three: Humans, the Xeelee, and the Photino Birds.

There are at least two civilizations scoring really high on the Kardashev scale. Both of these species inhabit stars and are at war because one species needs red dwarfs and the other black holes or something similar.

All three species are pretty advanced, and the Xeelee are at least a Type III civilization. They prefer to live on black holes, while the Photino Birds like to live off stars (is that where the red dwarfs come in?).

One of these mega-species is also at war with the humans, and their battles and tactics include time travel.

Humans are at war with the Xeelee, and the second novel, Timelike Infinity, uses time travel, where humans far in the future have developed the ability to travel through time.

The economy of the human civilization relies largely on the war effort, and at some point the ending of the war bankrupts Earth.

I haven't found evidence of this yet.

EDIT: Additional fact came to mind: One of the mega-species might have evolved only moments after the big bang, making it ancient.

The Xeelee were formed soon after the Big Bang.