Paladin's Shield

Solo, you get defense and immunity to knockback and that is the whole item. The knockback part is genuinely useful in a dungeon full of things trying to bounce you into a spike ceiling, but nothing else it does has any effect with one player in the world. Everything below needs somebody else standing near you.

While your own health is healthy, every teammate inside the radius takes a quarter less damage and you absorb that portion instead. The split happens after their defense and damage reduction have already been applied, and then your own defense and reduction cut into your share again. A wearer built like a wall therefore deletes damage from the party rather than relocating it. A wearer in a mage set just moves it onto someone with fewer hit points to spare.

Wearers do not pay the tax for each other. If everyone in the group has one equipped and stays in range, all of them get the reduction and nobody absorbs anything, which is easily the strongest way to run it. When there is one unprotected teammate and several wearers, the closest wearer picks up the hit, and if two are equally far away the tiebreak goes to whoever joined the server later.

Redirected hits count as real hits on your end. Your invincibility frames start, on hit accessories like the Star Cloak and Honey Comb fire, and a Cross Necklace changes how long the resulting immunity lasts. Dodge effects will not get you out of your own share. The item also does not check whether the transfer will kill you: sitting above the health cutoff means nothing if the incoming portion is larger than what you have left, and there is a dedicated death message for exactly that outcome. It ignores hazards that are not enemies, so a teammate wandering into lava is their own problem, and it will not try to share an instant kill.

It is a proximity effect, not a party wide buff. Split the group across a large arena and the protection quietly stops with no message telling anyone it lapsed. In practice the item wants a team that fights as a clump, which suits invasion events and boss arenas far better than it suits exploring.

Hold onto it, because it later becomes the Hero Shield or the Frozen Shield, both of which keep the sharing behavior and stack more on top. Even a solo character should bank a spare for that reason. It also pairs with the Brand of the Inferno, where having a shield accessory equipped is what lets you block an incoming attack and collect the buff that weapon is built around.