In dire need, the caster can sacrifice their life and soul for the sake of a message to an ally. If they have any doubt about whether this action should be taken the spell will fail.  At their utterance, they willingly let go of their own life. Death takes them immediately, Spare the Dying and Healing Magic are already too late to be helpful. The soul of the caster leaves the body in that moment to deliver a message. This message functions in the same way as the spell Sending except the target can be on any plane of existence. Once the message is delivered, the soul disperses causing the caster to be impossible to resurrect. This spell requires utter certainty to cast. If enchanted into an item, this certainty is not so restrictive, however the consequences remain the same