Fourth Wing’s Iron Squad must be expanded on in the series’ upcoming third installment, Onyx Storm, especially one member who has been underused so far. The Iron Squad is the unofficial name of Violet Sorrengail’s military section at Basigath, which is Second Squad, Flame Section, Fourth Wing. She and her section earned the moniker and corresponding patch during their first year as they were the squad that lost the fewest people since Parapet.
https://screenrant.com/onyx-storm-expand-fourth-wing-iron-squad-sawyer/