He is from the new expansion.

Are you sure you don't mean "Cellar Door", which Tolkien thought was exceptionally beautiful phonetic pronunciation?

Or "Celeborn", Gladriels partner?

There is no new spoiler released, so i'm not sure where you saw this. if you could be more specific it would help.

He is talking about Celador, the ranger ally in the second quest of Heirs of Numenor. Unfortunately I don't know who he is and my quick and lazy google search came up empty. I'm sure Rich or another expert will chime in about who is his, or whether he was created by FFG.

I'm pretty sure he was created by FFG, but I could be wrong.

He's a made up character. I'm pretty sure FFG got the name from Cellar Door. I say so because Tolkien loved how these two words combined sound. He stated it more than once in his life.

however in tolkien, C is pronounced as Keleborn….so i think it would be prounced Kelador

rich

In another world, it's a drunk septon's name. Maybe FFG got the name from there?