Why are the Alpha Legion here?

[Aya]

I really can't think of any legitimate reason for the Alpha Legion to operate in subsector beyond Relic thinking that Eliphas shouldn't be killing Black Legion soldiers.

[Waylander0719]

Alpha legion is everywhere, always doing subterfuge and infiltration. its kinda their thing. You should read legion the horus heresy novel if you want to know more about them.

[Nino_Chaosdrache]

Maybe it is, because Eliphas and Araghast have failed to conqier Aurelia and now they are taking he command to make sure that this won't happen again. Or Khyras made a deal with them after Eliphas has been defeated again. The last reason, whih might be possible is that the Alpha Legion soldiers there are also followers of Khorne like Khyras is.

On the other side, you can also ask why there are Alatoic and Biel- Tan Eldar in the system when you originally just had to fight against Ulthwé Eldar in Dawn of War 2 and Chaos Rising.