That's when I reach for my gigawatt plasma rifle

Back in the 60s, Harry Harrison wrote Deathworld, a trilogy of books about a planet with exceptionally dangerous native life. British scifi author Neal Asher has taken the concept and added his vision of evolved humanity to the mix. His book, the Skinner, is a wild tale of vengeance and interstellar politics.

The planet, Spatterjay, on which the story is set has a strange ecosystem. Large leeches have evolved a viral symbiont which confers high survivability and potentially immortality on its victims. The advantage to the leeches is that it can eviscerate a victim and eat it again later after it recovers. Humans that are bitten become nearly immortal (there are thousand year old characters) and super tough. If they fail to take in human food they eventually become a leech themselves (mmmmmmm, Shai-Hulud.)

The author uses the planet's environment and its effects well (a case of a human ultimate fighting match is rather nasty), but the focus of the story is on a number of characters who have come to Spatterjay. One is an agent of the Hive, the intelligent group mind of hornets. One is a 700 year old reification, a dead man walking who wants vengeance. Two more are war criminals working together for opposite ends. All of these are being watched by the Warden, an AI that represents the largest human government. It eventually plays out in classic scifi manner, the battle of the badasses, but it is very well done.

If anything suffers, it is characterization. With ten or more point of view characters and action on multiple fronts a number of characters that appear to be central end up being tertiary. The main character, if one can be said to exist, is not quite as developed as I would have liked, but the book is well worth reading despite it.