This arc is different in a fact that the entire story and its background is so far into the future.
Most of arcs occur between 9600 ~ 9800. This arc is way far into the future in 12xxxx. In other words, this ac is pretty much standalone and can be read without having read any of stories of Two Clusters.
The universe is being ravaged by unknown entities. Humans are on verge of total annihilation. But, somewhere deep in a nebula, pirates rise up.
[Alien arc] [1] [Gallo] [12328].pdf
[Alien arc] [2] [Captain Cecilia] [12328].pdf
[Alien arc] [3] [The Hope] [12328].pdf
[Alien arc] [4] [Alucasa] [12328].pdf
[Alien arc] [5] [The Nebula pirates] [12329].pdf
[Alien arc] [6] [Sae the witch] [12329].pdf
[Alien arc] [7] [The Saviors] [12330].pdf
[Alien arc] [8] [Perpetual] [12329].pdf
[Alien arc] [9] [Seven days of fire] [12330].pdf
[Alien arc] [10] [Fallen Leaf] [12330].pdf
[Alien arc] [11] [Path of creation] [12330].pdf
[Alien arc] [12] [Allies] [12331].pdf