You need to make your own observations about the characters. The first and most basic point of the question is to find out if you actually read the book. If you haven't, no one can help you.
If you have, try this strategy for brainstorming:
- Write down a series of characteristics for one character. Then do the same for the other.
- Now compare the lists for opposites. Is there anything in one list that has an item that is it's exact opposite in the other? Those two ideas then form one point on which they are opposite. Write a third list of those points on which they are exact opposites.
- Now study the third list. Make lists for the following three questions:
- Are there any points there where the pairs of opposite characteristics fit together to produce a beneficial effect? Make a fourth list, showing these points, specific points in the story where these matches are apparent to you..With each item, write down how it is that you can tell.
- Do the characters help each other out? Make a fifth list for these instances or patterns. Write down the specific points in the story where these forms of helping occur
- Do they fill in for each other's weaknesses? Male a sixth list for theses instances or patterns. Write down specific points in the story where they occur. Write down how you can tell that the helpfulness is in fact helpful, who benefits and how.
- Do they somehow strengthen each other by being opposite? Make a seventh list of the ways in which they do, writing down specific points in the story that show you the strengthening and explain why you think the characters are strenghtened in each specific point.
- Use the fifth, sixth and seventh lists for this step. Write one or more paragraphs for each list. Once you have written these paragraphs, try putting them in different orders. Try every possible sequence. So if you wrote only three paragraphs because each list only gave you enough information to make one paragraph, try them out 123, then 132. then 213, then 231, then 312, then 321? Which order seems to make the most sense? Use that order. Then write a brief paragraph that sums up what is in the three paragraphs and use it as your introductory paragraph. Then reread what you have written. Think hard about what it all means, what it says to you, what it implies in the world at large. Write your thoughts down in a brief paragraph and use that as your concluding paragraph.