Mercutio who is Romeo's best friend is another character who is to be blamed at a lesser extent for the deaths of Romeo & Juliet. If Mercutio hadn't insisted on fighting with Tybalt when he sarcastically says "here's my fiddlestick, here's that shall make you dance" (Act 3 Scene 1, Line 41-42) implying that he is about to take out his is sword and fight him. If it wasn't for that quarrel Mercutio wouldn’t have been killed and Romeo wouldn’t have had to kill Tybalt in order to take revenge for his friend Mercutio. In this case, Mercutio is to be blamed because if he didn’t start the fight with Tybalt Romeo wouldn’t have been banished for the killing of Tybalt and he wouldn’t be away from Juliet. In my opinion I think that Mercutio was trying to defend Romeo and stand by his side, he did not really intend to fight Tybalt but he had to when Tybalt was about to attack his friend, therefore Mercutio is a hero for saving Romeo's life and keeping the story for us because if Romeo had died then there wouldn’t have been a Romeo & Juliet.
This fight also shows me that Tybalt is also to be blamed for making an issue about Romeo & Benvolio gate crashing the Capulet's party. Tybalt had issued the challenge for the fight which Mercutio took care of. Therefore Tybalt takes more blame because he ignored the advice of Capulet who told him "Content thee, gentle coz, let him alone" (Act 1 Scene 5, Line 64), Capulet also says "Show a fair presence, and put of these frowns" (Act 1 Scene 5, Line 72). In my opinion, Tybalt is a trouble maker as he always tries to make big problems of the simplest issues. If Romeo's presence was really disturbing then Lord Capulet would have taken care of it but he doesn’t mind. Tybalt tries to start a fight with the Montague's at any chance given therefore that makes him a key role in starting most of the problems. Until now all those actions by the different characters are linked.
Another character involved at a lesser extent is Lady Capulet because if she had backed up her daughter Juliet rather than Lord Capulet when he demanded that Juliet should marry Paris, then Juliet might have admitted what she had done. This makes Lady Capulet another character to be blamed when she says "Marry, my child, early next Thursday morn" (Act 3 Scene 5, Line 112) to her daughter shows that she doesn't care about how upset her daughter really is. Lady Capulet does not want to argue with Lord Capulet about the marriage because she thinks that her daughter will be safe with a gentleman. She does not push the matter when Juliet disagrees instead she says "Here comes your father, tell him yourself" (Act 3 Scene 5, Line 124).
At the start of the play Capulet seemed to be a caring father when he refused Paris's offer to marry Juliet because "She hath not seen the change of fourteen years" (Act 1 Scene 2, Line 9) and he insists that he will only marry Juliet if she consents. But in this scene he loses his temper "Hang thee, young baggage, disobedient wretch!" (Act 3 Scene 5, Line 160) because Juliet refuses to obey her father's demand and marry Paris on Thursday, the quote "And that we have a curse in having her" (Act 3 Scene 5, Line 167) clearly shows how angry and furious Capulet really is.
The Friar is also partly to blame because he gave Juliet a potion that would make her seem dead. When his messenger Friar John failed to inform Romeo this made Romeo think that Juliet has really killed herself. Sad and depressed Romeo decides to kill him self and lie right next to his love's grave. Although he is to blame for the deaths of both of the lovers, his intention of marrying them was a good intention. Friar Lawrence's Intention was to stop the long lasting feud between the two families which was why he insisted on marrying Romeo & Juliet. Friar Lawrence's hopeful action turned into a disaster and starts to make the Friar's image to the audience or reader as an irresponsible man.
Fate or bad luck is also involved in the lover's deaths because if Romeo hadn't taken a sip of that poison before Juliet opens her eyes he would have been reunited with her. There are a lot of small actions that were involved in the lover's death that could be considered as fate or bad luck. An example of this is Friar John's failure to deliver the letter on time due to the plague that hit a town which he was passing through, while he is delayed Romeo's friend tells Romeo about what had happened to Juliet which makes Romeo go back to Verona as fast as he could.
A much more involved character in the deaths of the lovers is Lord Capulet because if he hadn't insisted that Juliet should marry Paris she would have had a chance to meet up with Romeo again, but when she discovers that she doesn't have a choice she decides to kill herself.
In my opinion Lord Capulet insisted on Juliet's marriage to Paris because he loved his daughter and wanted to keep her away from all the troubles going around. He knows that Paris is a noble gentleman who is rich and quiet capable of taking care of Juliet. He might have not given a choice to Juliet about marrying Paris because he might think that after tybalt's death who used to be like a brother to Juliet, there was someone whom Lord Capulet trusts to take care of Juliet.
Apart from the lovers, I would blame Friar Lawrence the most. Although his intentions were good, he took great part in concluding to this devastating end. I would also blame Juliet's Nurse as one of the most influential characters in the lover's death because she had helped get them married without letting the families know. She has also supported Juliet in all what she did and never advised her to let the family know. This makes her a great influence since she had supported and encouraged this marriage although it was wrong.
The lovers are also to blame for their own deaths because they hid the truth from their families. They might have had their reasons but if they didn’t hide the truth from both families then there might have been a chance of them uniting together. Romeo is also impatient and doesn't wait to know the truth, he drinks the poison as soon as he finds out Juliet is dead. In my opinion if the lover's had told their families about their love story there might have been a chance of a successful relationship.