Wise Man's Reincarnation: Five Kingdoms summary:
A world of war that has lasted for 100 years. Fuugo and Roka are childhood friends of the Kingdom of Asdorm. When the fates of two people who were once separated are reunited, a new threat that has never been seen before strikes them. Einstein and Edison. Genius greats who have been reincarnated in a war-torn other world compete with all their best intellect, the Five Kingdoms War begins.