Chronos

Chronos  is a temporal bounty hunter in the service of the Time Masters.

Chronos was sent by the Time Masters to bring Rip Hunter in, and also to do the assaination job they tried to give to Rip. Being from the future he has lots of futuristic weaponry and artillery as well as the ability to check the signifance of any one he sees in the future

Chornos is out to prevent the heroes from changing the timeline since the TIme Masters don't want them interfering with how events should go and will do whatever it takes to get the job done.