Usage patterns
正義を守るto uphold/protect justice
He took risks to uphold justice.
正義のために戦うto fight for justice
They kept fighting for justice.
正義を貫くto stick to one's principles of justice
He held firm to his sense of justice to the very end.
正義を実現するto bring about justice
The judge worked to bring about justice.
Expressions
正義の味方champion of justice; knight in shining armor; crime avenger; hero; superhero