I was looking this up before when wondering how to refer to Jenred, the king before Velax. As long as he's paused (in-game, he's in a coma), referring to him as "King Jenred" seems fine, as that's the way history refers to dead Kings. King Edward I is still King Edward I, even though he died more than 700 years ago and isn't King right now. But when he comes back, I can't really call him King Jenred any more, as he's isn't the King. But Lord Jenred or Sir Jenred doesn't seem to accord him the respect he would deserve from having built Arcaea up from almost nothing.
I think King Jenred would be just fine. Or, simply as "His Majesty" perhaps "Your Highness"
It depends honestly. If I was trying to insult Jenred I'd simply call him Sir Jenred or Lord Jenred. If I wanted to show him the respect he deserves I'd show him deference even as the reigning monarch of Arcaea.
Alternatively, if you really want to show him respect, you can grant him a new title such as "Lord Arcaea." That would certainly be a bit flattering. If your character stands by your statement here, then it would also fit quite well I think.
