Tower Shield Master

You use shields not just for protecting yourself but also others. You gain the following benefits while you are wielding a shield:

• If you are subjected to a damaging effect (such as a dragon's breath weapon or a spell) that targets creatures in a line, cone, sphere, or cube, and imposes a Strength, Dexterity, or Constitution saving throw, you can use your reaction to interpose your shield between the origin of the effect and yourself. This reaction allows you to take no damage rather than half if you succeed on your saving throw, and each creature in a 15-foot cone - originating from you and pointing away from the effect's origin - is considered to be behind half cover for their saving throws against the effect.
• You can add your shield's AC bonus to your saving throws against such effects, should you take your reaction to shield yourself and those behind you.