WN/Rimuru's Twelve Guardian Lords

"Altight then, Benimaru. Do you know as of today you might even become a demon lord?"

- Rimuru

Rimuru's Twelve Patrons [十二守護王,  Juuni Shugo Ou, literally meaning "Rimuru's Twelve Guardian Kings"] are the top 12 executives of Rimuru Tempest. They are those subordinates who have been awakened as True Demon Lords and have been bestowed a title of a "Lord".

Among them, 7 were awakened after successfully defending against the Eastern Empire and the remaining 5 were awakened before the Tenma War, after Guy had given Rimuru 500,000 souls to evolve Mizari and Hirari.

These executives are:
 * "Flare Lord" Benimaru
 * "Star Lord" Ranga
 * "Dragon Lord" Gabil
 * "Barrier Lord" Gerudo
 * "War Lord" Shion
 * "Demon Lord" Diablo
 * "Chimeric Lord" Kumara
 * "Mist Lord" Zegion
 * "Gehenna Lord" Adalman
 * "Killer Lord" Testarossa
 * "Pain Lord" Ultima
 * "Menace Lord" Carrera

Chronology
Rimuru initially had 945,000 souls after defeating the Eastern Empire. He used 10,000 souls to partially revive 700,000 Empire soldiers, 700,000 souls to awaken 7 of his subordinates, 5,000 souls to name Wenti, and 20,000 souls to let Ramiris name the Four Dragon Kings (Zephyrus, Boreas, Notos, Euros), thus leaving him with 210,000 souls.

Right when the ceremony was done, Guy Crimson, who was surprised at the sudden awakening of several Demon Lords, came flying and demanded an explanation and after having conversed with Rimuru, requested that he awaken his two subordinates, Mizari and Hirari, as well. Accepting, Rimuru requested Guy for 500,000 souls with Raphael's bold and daring swindler's advice.

Although the ability of Gluttonous King Beelzebuth required around 100,000 souls to evolve a capable being into True Demon Lords who did not have the Demon Lord's Seed (so he actually only needed to request for 200,000), Raphael took the chance and asked for more since Guy did not know of the actual soul requirements. This took into account all of Rimuru's remaining subordinates who were capable of evolution.

Once Mizari and Hirari arrived, instead of directly using 100,000 on each, Rimuru steadily infused them with souls until they started evolution. This caused him to use only 180,000 souls total (he only needed to provide 90,000 each because Guy once upon a time tried to evolve those two using 10,000 souls as well, but failed), and leaving him with 530,000 souls in stock.

Later, before the Tenma War began, Rimuru spent 500,000 souls and evolved his remaining "Lords".

Benimaru
After the war against the Eastern Empire, Benimaru was naturally selected to be the first person to receive post-war rewards. Although he was surprised that his reward was being awakened as a True Demon Lord, he gave up and prepared himself for his new powers.

Rimuru gave him the title of "Flame Lord" and transferred 100,000 souls into his being through the soul corridor to commence the evolution. However, nothing happened.

It seemed there was another requirement. Since the concept of lifespan becomes meaningless when one awakens as a True Demon Lord, there is no need for reproduction anymore. As the leader of the Ogre tribe, which was in the brink of extinction, unless Benimaru bore kin, his evolution would not begin.

"You better be resoluted, Benimaru. Momiji, come forth! I hereby recognize the binding of souls between you and Benimaru!"

- Rimuru

And thus Benimaru and Momiji were engaged. Later, after the ceremony, their official wedding took place.

Before the Tenma War, when 'everything was done', he automatically awakened as a True Demon Lord, and evolved from a Fair Oni into a Flame Spirit Oni (Upper tier Diving Monster Spirit). Thus, carrying on his post as one of Rimuru's three strongest subordinates.