How is Romeo a tragic character?
Romeo is a tragic hero for two reasons. First, his situation is tragic. He is a Montague and he falls in love with a Capulet. The two families, bitter enemies, have been feuding for many years. His is truly a forbidden love. As Juliet reminds him as he scales the garden wall to visit her, if her male relatives find him, they will kill him.
Second, Romeo has a tragic personal flaw: he is too impulsive. Like a typical teenager, he lives very passionately in the moment. For instance, he and Juliet marry a day after they meet, and even that feels too long to him (and to her as well for that matter). Therefore, when he does not receive the message that Juliet is faking death and finds what he thinks is her corpse, we are not surprised when he acts impulsively and immediately kills himself. If only he had waited a little while! But that would not be Romeo. He commits suicide. Juliet kills herself when she finds him dead, and for both the end is tragic.