In Shelley's Frankenstein, injustice is revealed mostly in the character of Victor. He not only creates a monster and fails to take responsibility for him, but then acts as judge and jury, condemning him even after the "monster," as Victor refers to him, tries to talk to him. And Victor, for the most part, rejects his creation based on appearance only.
Innocents also suffer in the novel. Justine is mistakenly condemned for a murder she doesn't commit, and again Victor has a hand in it. He not only creates the monster, but knows Justine is innocent and doesn't interfere. Elizabeth fights for Justine's life, but Victor does not.
Rejected by Victor, the monster, of course, kills numerous innocent people as well. Fairness and unfairness are in play from early on in the novel, beginning with Victor's first rejection of his creation.
Injustice caused by Victor is far-reaching in the novel.