AntiStateQuixote
Enemy of the State
Protection
Fighting Style Feat (Prerequisite: Fighting Style Feature)
When a creature you can see attacks a target other than you that is within 5 feet of you, you can take a Reaction to interpose your Shield if you're holding one. You impose Disadvantage on the triggering attack roll and all other attack rolls against the target until the start of your next turn if you remain within 5 feet of the target.
Unless I'm missing something, a pair of warriors each of whom has the Protection Fighting Style can stand adjacent to each other and use their Reactions every round to protect one another against all attacks.
Did we just get a Shield Wall option for paired warriors? I could see a line or group of such warriors working together to expand the protection to even more comrades.
In a line: each warrior protects the person to his/her right (only one person on the left end of the line doesn't get the protection).
In a group (2x2 grid, for example), each warrior protects the person counterclockwise in the group, or just pairs up (left/right or front/back).