THE BACK

this spell Buffs your teammates and allies with its own type of damage called back damage once the back is facing the opponent/opponents  it will also do damage the exact same amount of damage as you have taken in the round before but the damage type will be back type. any damage taken on the back as this spell is active that damage will also be dealt to the attacker that deals the damage as back damage. you will not be able to turn back around until the spell ends, or unless you cancel it, but upon cancellation you'll take double the damage that you have received the last turn, can still do actions that doesn't require you to face the certain opponents and doesn't move your back away from your opponents.

no matter what resistance or immunity your opponent has, say your opponent has magic immunity  and your teammate  uses a spell on them  that opponent with the immunity would still take damage because the spell is imbued with back damage

If taking a fatal blow that would require a death saving throw, well this spell is activated you get an advantage on the saving throw. if you have a Spell, item, or certain ability that will also give you an advantage on a saving throw this spell will allow you to make two death saving throws.