Gene Forrester is the protagonist in A Separate Peace. Since the story is narrated from his point of view, most of the insights into his character come through interpretation of how he interacts and reacts to the other characters in the story.
Gene is not a leader. He is willing to follow Finny's lead, even when it takes Gene out of his comfort zone - except for those times when he rejects Finny's friendship and attempts to carry on independently.
What was I doing up here anyway? Why did I let Finny talk me into stupid things like this? Was he getting some kind of hold over me?...it would never have occurred to me to say, 'I don't feel like it tonight,' which was the plain truth every night.
Gene does treasure friendships and is loyal to his classmates, when he's not conflicted about how their actions impact him. On his way to meet with Leper after the arrival of the telegram, Gene creates his own hopeful interpretation of the telegram's meaning.
Leper had 'escaped.' You didn't 'escape' from the army, so he must have escaped from something else...Leper had escaped from spies.
Gene is intellectually very capable, but he is insecure about his relationship with Finny. He is very aware of his conflicting feelings about Finny and doesn't know how to deal with them; at times he avoids them, at times he attempts to deal with them directly.