D−1.
Ren Xiaosu instilled P5092 with great hope by telling him that with his willpower, it would not be a problem even if he were to summon more than 10,000 martyred spirits. In fact, Ren Xiaosu wasn't even sure of his upper limits when it came to summoning the martyred spirits.
When he was at the Kingdom of Sorcerers, Melgor told him that the stronger a sorcerer's willpower was, the larger their inner world of meditation would be. While everyone else only started off with a leaf in their inner world of meditation, Ren Xiaosu's contained an entire world.
When it came to Ren Xiaosu's willpower, it always felt like measuring it was close to impossible.
Moreover, Ren Xiaosu even told P5092 that not only would he be able to summon over 10,000 martyred spirits, but he could also let them live in the outside world without having to endure the darkness of the Martyr's Palace.
