So kids, I know sometimes I sound like a shill for Black Library, but in Deliverance Lost, the characters from Raven's Flight are in it, and the events of the latter are referenced heavily and, although I haven't read far in, I'm pretty sure they'll be a plot point later.

Minor spoiler
Also, there are literally dozens of Alphariuses running around at the same time - it turns out that some Alpha Legionaries undergo psy-treatment to become Alpharius, basically meaning that he can't be killed. It also means that the author (Gav Thorpe) doesn't have to write individual personalities for each Alpha 'cause they're all the same guy.

Also,Alpharius can call Erebus out on the bulls* artist that he his.