Building off of this great question, does any character both survive and make an appearance in all seven Star Wars episodes? For example, we know that Chewbacca is certainly alive for the entire time, but he doesn't show up in prequels 1 and 2. The only character that I can think of is R2D2, but I feel like there must be at least one more.
Assuming you include droids then there are only two characters who appear in all seven films, C-3PO and R2-D2. Obi-Wan Kenobi also makes a brief voice cameo during Rey's flashback bringing the total to three.
Out of universe, Anthony Daniels is the only actor who has actually acted in all seven films.
Separately, I would also suggest the Force as a character:
- Qui-Gon Jin tells Obi-Wan to be mindful of the living Force.
- Also, Yoda refers to the Dark Side of the Force as being seductive.
- Episode VII is The Force Awakens, which implies awareness.
And the one not like the others: The Force is Anakin Skywalker's father.