Overlord, Vol. 14 (manga)

A caravan flying the flag of the Nation of Darkness has been attacked by a noble who hails from the Re-Estize Kingdom. Coincidence...or conspiracy? Either way, Nazarick interprets this as an act of brazen hostility and readies for war! The people of the kingdom, still reeling from the disastrous battle at Katze Plain, reluctantly prepare themselves for another bloody day. When a ruthless campaign of extermination begins sweeping through the entire country, and near-certain doom looms over them all, every single living being within the kingdom's borders must decide for themselves how to weather the storm that is Ainz Ooal Gown!