Desdemona- Arguments see that Desdemona is a stereotypically weak and submissive character. This is particularly evident in her murder, where she accepts responsibility for it in response to Emilia's question "who hath done this deed?" where she answers "Nobody. I myself. Farewell./ Commend me to my kind lord, farewell." In the end, Othello puts an end to Desdemona's words which made her so powerful.
However, this is not entirely true, as she is assertive, certainly more than would traditionally be expected. Although it is contradictory that she is a faithful, self-effacing wife, while having a bold, independent personality, this contradiction may be done intentionally to replicate her defending her marriage to her father, in A1S3, and then almost immediately having to defend her fidelity to her husband. From the beginning, she is an independent person, but struggles to then convince Othello she is not too independent.
E.g., A1S3, "My noble father,/ I do perceive here a divided duty," and in A4S1, after Othello strikes her, she retorts "I have not deserved this," as well as in her convincing Othello forgive Cassio.