Really, the samurai was THIS close to killing himself. The sheer monotony and despair of his impossible task was sure to do him in sooner than later. Aku threw a wrench into his plans by getting creative and having kids, heck, worst case scenario for Aku, Jack kills him in the future but the past is still doomed, but no, Jack got the best possible result thanks to Aku's tomfoolery.

I AKU, THE SHAPESHIFTING MASTER OF DARKNESS… Did not plan on this.