Ah, I agree that knowing the Impact Character will help. (That's why I brought it up. ) What I meant was more, if a character is jumping around through time and space, it will be kind of tricky to pick an Impact Character who doesn't also jump. You could pick one character and have the time traveler visit them in various stages of their life.* You could also have the traveler return to the period with the Impact Character every so often to improve their relationship. You could have a position, like the President, and the traveler interacts with different people occupying that position. You could do handoffs, of course, and have a bunch of disparate characters who all represent the Impact Perspective in different ways. Lastly, you could dodge the question and make the Impact Character another time traveler: perhaps a magic talking hairpin** that guides and teaches the traveler, or a rival time traveler with none of the respect and awe of the worlds they pass through.
Or, I suppose, you could have an Impact Character whom the traveler doesn't interact with beyond their primary meeting, but who is still felt in spirit, both their Impact and the bonds of their Relationship.
*I've had this idea lying dormant in my mind of a story that's essentially the reverse of this: an expecting couple are visited by the future versions of their child, who visits every so often to protect them and help through the rough times. Also related, my idea where a man goes back in time to adopt himself as a teenager after his parents died unexpectedly.
**Weird idea, I know, but it's partially based off of a video game where the player character's mentor is a talking hat.