Excessive hemolysis (often due to anemia) will cause what condition in the urine?

Excessive hemolysis will give darkness of the urine due to hemoglobin metabolite.

Hemolysis is an excessive lysis of red blood cells. This condition will release a lot of hemoglobin in the blood, which will be metabolized to urobilinogen, then to urobilin, and passes through the urine and gives a darker color to it.