The protagonist is surely an important character. He is the one who faces the last temptation and his journey forms the core of the story.
Then there could be an antagonist. This character might be the source of some of the temptations, either directly or indirectly. They could represent the worldly desires or the forces that oppose the protagonist's spiritual growth, adding conflict and drama to the story.
Obviously, Jesus Christ is the central and most important character. His thoughts, actions, and spiritual journey are the focus of the novels.
I'm not entirely sure as it depends on the specific graphic novel. It could be a protagonist who is an everyman figure, representing the common struggle with temptation.
Since I haven't had the chance to read the 'last temptation graphic novel', it's hard to say exactly who the main characters are. However, based on the title, there could be a central character who is on a path of some sort and encounters the 'last temptation'. There may also be antagonists who try to manipulate or influence the main character to give in to that temptation.
Rey is very important. She's a strong Force - user and her growth in the Force is a major part of the story. Finn is also crucial. He has a unique perspective coming from being a former stormtrooper and is now fighting for the Resistance.
The tycoon himself is an important character. He is the central figure around which the story revolves. There is probably also his love interest, who adds a different dimension to the story, often challenging his values and priorities.
I don't know specifically since I haven't read it, but usually there are protagonists who drive the story forward.
Harry Black is an important character. He is sort of a central figure in the web of stories within the novel. His actions and experiences are used to show different aspects of the urban life in Brooklyn.
There is also Cecilia Brady. She is involved in the story, having a connection with Monroe Stahr. Her perspective gives us an insight into the world around Stahr and the relationships within that world. She is part of the complex web of characters.
Hawkeye is the most important character. He is a skilled frontiersman. Chingachgook, one of the last Mohicans, is also very important as Hawkeye's friend. And Uncas, Chingachgook's son, is another key figure in the story.
Perhaps there is a family member, like a grandchild or a niece/nephew who has a special connection with Ptolemy Grey. This person could be important in terms of the emotional support they give or the way they help him face his last days. And there could be a doctor or a medical professional who is involved in his care.