[NaughtiusMaximus]

Longstreet's stategic and tactical thinking beautifully anticipated the First World War 50 years before its time. It cost the European nations millions of lives to discover what paying attention to Longstreet could have taught them.

[The Iguana]

Also inventor (in large part) of the transverse trench. Probably the one true tactical innovation to emerge from the Civil War.

Which saved a lot of lives.