Detailed Instructions: In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Q: Sentence1: Brian was a soldier. Sentence2: He enjoys talking about his adventures. Sentence3: Brian tells his grandson to avoid joining the service. Sentence4: But because he speaks of his service fondly, his grandson joins anyway Sentence5: Brian is saddened his grandson didn't take his advice.
A:
Brian, Grandson