"Time" or "Timer" is a suffix to describe a noun from or located a different time. The word is used frequently in cases involving time travel. By all means, all individuals who would be described with the word "timer" is a chronoterrestrial, in a basic sense.
A Past Timer is some one or something from the past. Past Time can also mean located or even stranded in the past
A Future Timer is someone or something from the future. Future Time can also mean located or even stranded in the future.