As twins you share a very deep and special bond beyond that of most. When you take damage, you can use your reaction to divide the amount of damage you take in half and share that damage with your twin. When dividing the damage by two results in an uneven number, one of the twins must take the additional point of damage, the choice of which is up to the twin taking the original damage. Your twin has the option of resisting the damage if they choose to by making a Constitution saving throw with a DC equal to the amount of damage being shared. You can use this ability up to three times in a single day. The ability is reset following a long rest.