Chillin' in My 30s after Getting Fired from the Demon King's Army

Follows Dariel, a soldier in the Dark Lord's army who cannot use magic. Instead, he wields his intellect and initiative as an assistant to one of the Dark Lord's most trusted captains. But when the captain is summarily replaced, Dariel also loses his privileged position and is fired. In disappointment, he retires in a village of humans, getting a new start at life by using his abilities to accept requests for help.