The ranks of the death soldiers consisted of five:
The "Pueri Morturi,"- also called the "Rank of the Dead."
The "Peuri Renati,"- the "Rank of the Reborn."
The "Peuri Immortales,"- the "Rank of Immortals."
The "Peuri Deicidi,"- the "Rank of God-Slayers."
And finally the "Abaddon,"- the "Rank of the Destroyer."
The number of death soldiers in the first two ranks (Morturi and Renati) were uncountable, unimaginable.
But the next two ranks (Immortales and Deicidi) consisted only of 12 Soldiers each, a total of 25‐ these were the "Elites."
Every member was addressed by a number, the strongest and closest to the Abaddon Rank being No. 1 and the "weakest" (who was by no means weak)in the ranks of Decidi being No. 12.
No. 13, being the number of the strongest in the Immortales Rank, who was none other than Jack. And No. 24 being the weakest.
Another noteworthy thing: once a death soldier steps into the Decidi Rank they undergo what is referred to as a "turning."- a special process handled done by The Master himself, rumour has it that, the process is a demonification process, that changes a person into a Demon.
It hasn't been confirmed, but once they go through the process, they become unstoppable and unkillable. And they always wear masks- animal masks.