Episode 8.21 will see the introduction of a new character. This character will appear in episodes 8.21/8.22 and 8.23 and has the possibility for more appearances in Season 9.
His name is “Metatron” and is an aged angel, the scribe of God and has been around before the time of Adam and Eve. He is described as a cross between Obi-Wan Kenobi and Virgil Kent/Keyser Söze.
via Spoiler TV
So we WILL be seeing Metatron this season…and if it’s true that Ben Edlund wrote 8x21, then he’ll be the one introducing the character.