Hi, I am English learner. I have a question. "There is no one [that] I know of [who] deserves to love her."?

In this sentence, I know [that] is used as a relative pronoun because its antecedent is 'no one' and it includes 'no' before 'one' (I've learned we should only use 'that', not 'which' or other forms, when its antecedents include a negative such as 'no'), but I... show more In this sentence, I know [that] is used as a relative pronoun because its antecedent is 'no one' and it includes 'no' before 'one' (I've learned we should only use 'that', not 'which' or other forms, when its antecedents include a negative such as 'no'), but I have no idea why [who] is being used instead of [that] in the sentence. Because, I think the antecedents of both relative pronouns are same, including the same negative 'no'.
Anyone could give me an answer?
Please.
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