Throughout the battle, the role that Eisen took on was rather simple. All that he had to do was properly deflect the more large-scale attacks, whether it was through catapults or magic that was flung toward them. It wasn't really all that hard to do so either. While Eisen's element maybe wasn't particularly great for combat, it seemed like it was still decent at defending him, especially if he created a thick layer of metal on his skin where anything may impact, his hands in particular.
This way he could reach for whatever sort of attack may be incoming and then push it away without needing to worry about anything too much. As if he was wearing gloves, actually.
