The character Professor Snape may be one of the most difficult to analyse in the Harry Potter series. It is not until we have read the entire series that we realize what a complex character Severous is. Look at his actions in The Half Blood Prince. He appears to be completely returned to the dark side. With our limited knowledge, we believe Severous has been acting against Hogwarts, Harry, and Dumbledore the entire time. The truth, revealed in the final book, is really quite different. We cannot understand his character until we learn of his love for Lilly and his constant protection of Harry. Through all the books, we grow to dislike Severous Snape and readers generally find him to be an evil character. Near the end of the last book, we share the shock with Harry that Severous is actually the opposite of what we thought him to be. In the end, we see that Harry now holds Professor Snape in the same regard as Dumbledore when he names his son Albus Severous Potter.
I think Severus is one of the best characters in the series. He is as intelligent as Dumbledore, he is a master in hiding his true feelings and emotions as well as thoughts, and he is the bravest man in the whole story. He is always giving his life to protect Harry.
His love for Lily Evans is stronger than any love shown in the series, his love makes him stand against evil, and protect the light Harry has inside of him.
He guides not only Harry, but many other pupils as Draco, of helps the nurse, helps Dumbledore himself. He is loyal to Dumbledore, he is fair towards his Slytherin pupils and house itself.
Through out the seires JK tries to give Snape a different direction. She tries to trick us into thinking he is an evil character, when in reality he is in the good side.
In the end of the last book, JK gives a twist in the tail and informs us that Snape is, at last, the one who gives Harry the best of helps, the one who guides him, the one who is all good and not evil.
Severus is a real hero, and I think that is the best cuality we can find in him while doing an analysis of the character.