Introducing our cast of characters...
William Tecumseh Sherman. Called "looney" by the papers after a mental breakdown in 1861. After a leave of absence, returned and quickly befriended Grant while serving in the Western front. Eventually rose to Grant's right-hand man, commanding the Army of the Tennessee on its "march to the sea."
Our man
Ulysses S. Grant. A prez for real! Famous for his struggles with alcohol and his habit of cigars (upwards of 20 a day, some sources report, perhaps exaggerating). Probably America's best general. Some call him and Sherman the first "modern" generals, for their abandonment of Napoleonic principles, their attention to logistics, their pragmatism (and disdain for Old War concepts of chivalrous combat), and their practice of "all-out war."
Our boy
George Henry Thomas. The Rock of Chickamauga. Bunked with Sherman at Westpoint. Delivered some crushing defeats to John Bell Hood, who had previously been a student of his.