How does otherness play a role in shaping a character’s identity in act 4 of The Merchant of Venice?

The theme of Otherness is central to the plot of The Merchant of Venice. By virtue of being Jewish in a heavily Catholic and frequently antisemitic city, Shylock is presented as an Other, a person who does not fully belong to the place he inhabits. Despite his profitable moneylending career, Shylock is unhappy with his standing in the community. It seems attempts at friendliness have been rebuffed by the gentile characters.
However, by act 4, when his money has not been delivered on time and his daughter has spurned her Jewish heritage, Shylock feels as if he is a victim of the system and no matter how successful or friendly he is, he will always be considered an Other. Antonio says that he will answer Shylock's hunger for vengeance "with a quietness of spirit" (4.1.11), but it is Shylock who has endured years of this same quietness of spirit. Though Shylock's actions are interpreted as those of a bloodthirsty madman, he insists that he "stand[s] here for the law" (4.1.141). Shylock's hunger for justice is not the sudden capriciousness of a bad person; it is the result of years of Otherness.