Ye are of your father the devil,
and the lusts of your father ye will do.
He was a murderer from the beginning,
John 8:44
As for those stained pages of history...................When atheists attack Christianity over all the supposed wars of the past it is held accountable for----they forget something. All the millions killed in the 20th century by an atheistic worldview. (Hitler implementing evolutionary eugenics resulting in the holocaust, Stalin, Pol Pot, Mao, North Korea's dictators, etc.)
In Christianity it can only arise as a VIOLATION of it's belief