WARNING: the following contains spoilers for Episode 32 of That Time I Got Reincarnated as a Slime, now streaming on Crunchyroll.
Rimuru is rapidly learning the ropes of international diplomacy and trade, and his new beast kingdom of Tempest has already put itself on the map in a big way. But this has also attracted many bitter enemies, including the Western Holy Church and the Kingdom of Falmuth, who have slain many of Rimuru's beloved citizens.
While Rimuru was away with Shizu's students, the Church and Kingdom laid siege to the city of Rimuru, and Rimuru himself returned to a scene of total carnage. The devastation left by Falmuth's troops has push Rimuru close enough to the edge that he might be on the verge of becoming a monster.
Among all the bodies lying in the streets of Rimuru's kingdom, one corpse, in particular, stands out: that of Shion, Rimuru's secretary and most enthusiastic fan. She gave her life to protect her friends from Falmuth's raiders, but the result is downright heartbreaking. Rimuru himself can survive just about anything his enemies throw at him, but if he can't protect the people closest to him, then what's the point? Thankfully, Eren and her adventurer friends show up with an interesting solution.
Eren explains a folk tale from the Sorcerous Dynasty of Sarion, where she was once a princess. Some time ago, a girl was born to a human mother and dragon father, and when her dragon pet (a duplicate of her father) was killed, the girl lashed out with her incredible powers, tearing down the kingdom and slaughtering tens of thousands of people. In the process, she became a demon lord, fueled by so much loss of life. That new power allowed the girl, Milim, to revive her fallen companion. Following that tale, it might be possible for Rimuru to also become a demon lord and bring back Shion.
Rimuru, now understanding that there can no longer be any peaceful diplomacy with Falmuth, resolves to wage war against the kingdom, including its three isekai heroes. Rimuru is now willing to do anything within his power to make things right and, after hearing of a 20,000-soldier Falmuth army approaching, he plans to slaughter them all and use their power to fuel his transformation into a demon lord. Falmuth took Shion away from him, and now he'll return the favor.
However, there's a loose end when it comes to Falmuth: the demon Myulan, a minion of demon lord Clayman's. Her heart is being held hostage by him, meaning Myulan is forced to obey his wishes. Rimuru confronts her, declaring that she must die, much to Youm's and Grucius' horror. Rimuru thrusts his hand into Myulan's chest -- but Myulan survives. Rimuru "killed" her for a few seconds at most, tearing out Clayman's artificial heart and swapping it for a new one. The heart that Clayman provided acted as a tracking device, allowing him to control Myulan's every move. But now Myulan is free and swears to fight on Rimuru's behalf.
Rimuru's enemies are great, but his honesty, kindness and strategic planning have all won over one ally after another, and he's proven himself, bit by bit, to be the leader his monster kingdom needs. However, with Shion's death, there's a real risk that Rimuru may fall to the dark side for good. He's already planning to massacre a Falmuth army and replace its king with Youm -- but just how much further than that will Rimuru go for his people? Everyone, friend and foe alike, may soon find out.
