1 hour ago, Yoritomo Reiu said:In terms of actual usage, none of the above would apply. The emperor/empress would be referred to as heika (陛下), either by itself or following their title (can't remember off the top of my head if that's tenno or kotei in Rokugani).
I believe I've seen Tenno used in L5R before. So I'd go with Tenno-heika.