He has been hunting the Omnibrine for an unspecified (but long) amount of time. He has resorted to attempting to kill it via any way possible, including attempting to kill Steve in order to prevent it from forming.
In the season finale he accidentally causes the Omnibrine to form (sort of) using a Motion Arrow.
Steve: Hunted; teammate
Alex: Temporary enemy; teammate
Omnibrine: Hunted, Soul-foundit in part