From publisher blurb:
Welcome to Ravagers of Time, the eleventh in our Monster Menagerie line of bestiaries. Each volume in this line presents a small set of monsters tied to a single theme, but spread over a range of CRs. For Ravagers of Time, that theme is time, and all the complex and convoluted creatures that manipulate, eat, and travel through time. In addition to timekeeping terrors from chronal dragons to wampus cats, we provide an insight into the nature of time itself, with a brief description of the timestream (the medium through which time flows) and some items, feats, and spells tied to time.
Fans of Rogue Genius Games’ two books on characters who manipulate time (The Genius Guide to the Time Thief and The Genius Guide to the Time Warden) will recognize many concepts from those books used here, and this list of time-sensitive monsters can easily be used to add a heavier time-element to a campaign. However, while these monsters work well with time thieves and time wardens, those books are not required to make use of this one. Each volume can stand on its own, or they can compliment each other in a campaign that includes all of them.
Like all Monster Menagerie books, this one covers a range of CRs, from the annoying and hard-to-pin-down CR 1 leap insect, to the CR 22 lord of time, the Chronal Dragon Great Wyrm. In a campaign where temporal magic is nearly unknown, a GM may consider treating all temporal creatures as gaining a +1 circumstance bonus to their CR for having powers players won’t expect, and may have more than normal difficulty .
So check your watch, set a schedule, and flip through these entries as quickly as possible, because with the timestream assassins literally killing time, you may be in a bigger hurry than you think.