While it is readable it's not important
The mutant race is still feeling the effects of Scarlet Witch's attack on them that has left them near extinction. Henry McCoy aka the Beast believes her hex that has robbed the mutants of their powers can either be reversed or the mutant gene can be restored. He embarks on a personal mission across the world for any type of answers. -summary
X-Men: Endangered Species written by Chris Yost, Mike Carey, and Christos Gage collects a series of one shots that took place across New X-Men 40 - 42, X-Men 200 - 204, X-Factor 21 - 24, and Uncanny X-Men 488 - 491. The story is a follow up to House of M and Decimation as it covers the Beast dealing with the continued effects of M-Day, which is the event Scarlet Witch uttered the words "No More Mutants", thus removing the powers from millions of mutants leaving less than 200. Some of these people died instantly due to the removal of their powers, some were hunted and killed, while some were happy to be "cured". This story which is also the prologue to the X-Men mega event Messiah Complex, follows Beast as he refuses to sit down and do nothing about this situation.
I have never been a fan of the Beast as a member of the X-Men, X-Factor, New Defenders, or even an Avenger. He never did much for me and I always felt had Marvel killed him off he wouldn't have been missed, at least not by me anyway. I wasn't really too thrilled on a story focusing on him, but as a collector and since I have to be aware of these events this was a story I was going to follow no matter what. While I still enjoy this book I'm no where near close to being a fan of Beast. In any case, the writers accomplish their goal in making him interesting enough to somewhat carry this book alone.
The plot begins with Beast growing very desperate over the dilemma to the point where he considers selling his soul to the devil in a way; he seeks assistance from some of the worst individuals on Earth such as Dr. Doom, Arnim Zola, Mr. Sinister, High Evolutionary, and even Sugar Man to name a few.... That's desperation right there. Pandemic even goes so far to boast that he will raise a glass when the last of them dies. So this right here should at least provide an idea of what he has to deal with, therefore his loss of hope feels believable. Later on he finds hope in a rather unwanted ally in the form of his counterpart the Dark Beast, and they form a very uneasy truce. In fact, Beast can't control his hatred for the guy. This is when things get very interesting.
This story would have never survived the duration without Dark Beast raising the stakes. He wants the same thing Beast wants, but he knows that Beast must be willing to go all the way to save the mutant race; this means putting his morality on the line. At times the story feels kind of repetitive with Beast questioning himself, but this is also part of the reason it works so well. Most people already have an idea the path Beast is going to choose. However, the writing is solid enough to at least let us know that some temptation is there. Dark Beast is the show stealer though and he's given enough background for those unfamiliar to at least know that he is a psychotic butcher. The main problem I see here is the lack of action. This story is slow paced and relies on the character's and their situation; there is a fight towards the end I'm sure most people saw coming, but it felt too tacked on as if the writers wanted to throw some action in there just to have it.
The artist consist of Mark Bagley, Andrea Devito, Mike Perkins, and others across different titles so you can expect some inconsistency; the good thing is that the artwork is never bad and it flows so well with the narrative. The character designs are finely drawn, and I like how there's more of a difference between Beast and Dark Beast. At times the backgrounds are so pretty to look at from the chilling mountain snow caps, to the evening sunsets at a cemetery. It can also be a bit disturbing watching the mutants on the verge of execution in a death camp. Visually I can't think of anything not to like.
Along with the lack of action and even forced action; I also can't shake that this story is kind of meaningless in the grand scheme of things. It really doesn't add much to House of M and Decimation, it's not necessary going into Messiah Complex, and Beast really doesn't change as a character or come any closer to making peace with Dark Beast, despite Xavier actually respecting him on some level. It's an average story at best that will definitely appeal more to hardcore X-Men fans. If you don't fall into that category then you can skip this.
Pros:Interesting chemistry between Beast and Dark Beast
Cons:Lack of action will put off many, average, not very important