The Echo and the Ascians

[MrThinker]

but they have failed the first. its still there tormenting the alliance raid rlt , the world of darkness. one doesnt count

Yes, the Thirteenth, now known as the Void/World of Darkness, was not Rejoined. This was because there was no associated calamity on the Source, because the Ascians didn't know they needed it at the time. However there have been seven subsequent umbral calamities, and thus seven rejoinings. As Rosenstrauch states:

The shards that have been consumed via Rejoining during the Seven Umbral Calamities are as follows: The Fifth, The Twelfth, The Second, The Third, The Sixth, The Tenth, and the Seventh.

This info was revealed to us by Crystal Exarch during his explanation of how calamities work, where he shows the Shards and Source as orbs in a circle, implied to be First to Thirteenth going clockwise from the Source orb (the largest one).