Assassin's End by R. Kyle Hannah
All Rick Brewer wanted was to live a quiet, normal life. Stranded in an ancient land, he encounters nomads, pirates, and Vikings. No matter where he goes, he is destined to influence the future. Unknowingly, entire timelines are erased and new histories are created.
Assassin 101, assigned to track down a rogue agent, leads missions to 1914 Sarajevo, 1897 Paris, 1515 Puerto Rico, and 2001 New York. Partnered with the time-misplaced Assassin 12, they must find Brewer to repair the time-lines before their future is destroyed.
Leann Lassiter, a teacher in the Guild, must mold the next generation of Assassins. With the threat of history’s erasure, she spearheads the monumental effort to track down Brewer. How does one find someone who does not want to be found when he has the whole world and all of history to hide in?
As Leann works, Councilman Trion Mar supervises in the hope that she will not find the truth—a secret he would kill to protect.
As the time-lines spiral out of control, Assassin 101 must find and stop Rick Brewer in a battle that will determine the fate of mankind and history itself.