write on merchant of Venice as a story without hero and write about it as a story with a hero?

Your question does not make sense. Also we don't write stories on this forum.

I am really sorry I should have written this question in two questions. Anyway, what i meant is, Can we consider any of the characters as the hero of the play?

While reading it you will find a lot of characters so you will get confused about the hero and you might even think that it is without a hero. So is there a hero or not?

Thing about Merchant is there are no heroes. Shakespeare made sure that Shylock was not a hero or a villain without sympathy. If anything, it is the Christians that go too far at the end of the play stripping the old man of his family, wealth and faith. I'm not sure Elizabethans would have openly felt Shylock's pain but we sure do.