Nehan is a unique technology in Age of Empires IV: The Sultans Ascend available to the Japanese that can be researched at the Buddhist Temple or Temple of Equality starting in the Imperial Age. Once researched, the Buddhist Monk's Buddhist Conversion ability is upgraded to Nehan Conversion, which adds a 25% movement speed buff to surrounding allied units and reduces cooldown from 120 seconds to 90 seconds.
Nehan Conversion (Active): While carrying a Relic, attempts to convert all units within a four tile radius to its side. Any enemy units remaining within the radius at the end of a 6 second countdown are converted. Siege engines, Heroes, and other religious units are not affected. Upon casting, nearby allied units gain +20% damage and +25% movement speed for 20 seconds. Cooldown is reduced to 90 seconds. The damage bonus only applies to base damage, not bonus damage.