Ok, I've been reading the Angeld of Purgatory and these are some points that came up for me. These are all just my personal opinions of course and others will likely disagree.
1. Do the Chapter owe their psychic potential to Warp taint? That's what I read from the description of the daemon prince's explosion. And so wouldn't this mean that the Chapter is in fact tainted by Chaos? And if not, how come that they were not tainted by the power that affected them when it came from the Warp?
2. How would they remember the "legend of the Thousand Sons" unless they are very oriented towards forbidden knowledge and why would they follow the example of these traitors and heretics even if it was practical?
3. I don't at all like that some Inquisitors and and in particular that the Adeptus Astartes just poop out of the blue to help the Chapter out. I don't see the Adeptus Mechanicus giving their aid except for some serious debts owned to them. I think that either the marines should just lack their eyes or this link to the Mechanicus should be expanded upon.
4. I don't like the Tech-marine Lucys being an Untouchable. Considering that this Chapter is supposed to be be up by psychers I think that it both breaks the mood of it and it feels very uninspired to me. I don't like it one bit.
5. Regarding the homeworld I accept it without fuss, but I seriously doubt that it would turn even remotely into a hive world within a millennia, population boom or not.
6. I think that the starting stuff for coming from this Chapter is way to good. A +5 Characteristic and the bionic eyes should be well enough for them. In fact I would probably give them a +1 Psy Rating and a unique Chapter Psychic Power instead of any other bonus.
7. I think the Demeanor have potential but it really needs a to be expanded and worked on.
8. In the Battle Doctrines section it seems to me that you are both saying that these guys do not have a battle doctrine and that they do. I would probably refine it a bit to make it more inline with their unique advantage of their sight. Right now it feels to me that they have two separate parts that aren't really connected with each other.
9. Primarch's Curse looks good to me.
10. In the Advancement Table I don't get where the hatred against psykers comes from in the Chapter. That hasn't been expanded upon as far as I could see.
11. Don't at all like the Solo Mode Ability. To me it seems like this is more of a psychic power than a solo mode.
12. Psychic Powers looked ok, although to be honest I couldn't really discover a theme in them.
13. Wait! So every member of the Chapter goes to Terra for a Soul Binding? How the hell do they keep that silent since its a HUGE thing to go there and do this. I'm sorry but it don't work for me.
14. I don't like the idea of anyone welcoming an Untouchable with open arms. If he's tolerated and not killed by his brothers he should consider himself very, very, very lucky for every day that he lives. I would rule it that the Unbidden are simply killed by their former brothers.
15. While the name is the "Angels of Purgatory" I couldn't find much of either an angelic or a purgatory theme in the Chapter. But that could of course just be me who is narrow in my vision. But I think that the theme of the Chapter don't really go through it. I certainly couldn't really detect a single unifying theme across the Angels of Purgatory.
The Good Things.
- I like the idea of a Chapter of low level psychers
- Most of the overarching stuff is ok or good but there are several details that I think could be changed