Great start to a series. This has a few different types of characters that are all dependant on each other. Theain characters are sentinels. They have this tree tattoo that represents there life. When all the leaves fall their life is done. In order for them to not die they must find their female counterpart, not an easy feat because it is believed that there are not many, if any left to be found. Then Helen pops up.
Corny romance, first series world building, alpha males, and decent fighting action scenes. Book two is better, glad I continued with this.