Shieldwall

You know that you and your allies are stronger when wielding your shields together as one. If you are wielding a shield and within 5 feet of any number of allies that are also wielding shields, you and each of those allies increase their AC by 2, and gain advantage on Strength saving throws to avoid being pushed or knocked prone. This benefit extends to allies that are wielding shields and within 5 feet of a creature affected by this benefit. If a creature is already affected by this benefit it cannot gain it again.