Dean Vincent Houvardas 
Firewielders [EPUB ebook] 

In the ultra mega far future, some guy gets bored of existing, so he accepts a job in a different universe described as: 'the perfect excuse to throw your life away for a cause you barely understand’ in search of purpose.

instead, he finds a world devoid of it. The sun itself refuses to shine, but sparks of meaning still remain.

Warning:

Murder, depression, death, suffering, largely unnecessary swearing, you know the deal.