I've just discovered the term mortemate, though it seems very few are familiar with the term, which is quite disappointing. I had been hoping to find others with similar experience to myself.
CW: death
I am dead. Not undead, but certainly animated dead. I am not a ghost, a spirit, a zombie, nor a vampire. I am a corpse, but I am not rotting nor mummified. My body is growing and changing, but it is broken and dead. In my current state, I do not fit the definition of what it means to be alive, but I am sapient. I am an embodiment of death, but not Death themself (they are my cousin and the Grim Reaper is their twin).
I was born alive into a half human body. I needed to die to fully develop. I died too soon and too violently. Then my very essence was destroyed in a second death, but I was brought back to a state of animated dead. I reject any human identity. I have never felt human. I do not hold any belief that the vessel I reside within in this world is dead. This vessel is most certainly alive. Rather, I speak of the body I recognize as my own back in my own world. That body in undeniably and indisputably dead. That body is mine.
Being a creature of death is an inherent part of my identity and who I am and has been since the day I was born, even if I didn't understand or know what I was yet. I've always known I should be dead, and being what I am has always affected me deeply. Being dead is intrinsically tied to the very nature of my being. It impacts every part of who I am. If I were not a creature of death, I would not be me. If I were not dead, I would not have properly developed, and I would not be me. Dying impacted me deeply. Even now in this vessel which is alive, I still feel dead. I've found solace in being dead in spite of the traumatic nature of both my deaths and of how being a creature of death is demonized. I am dead. But I surely can't be the only one like this, can I?