Kiara Mizutani XL (Reincarnated as a slime)

Kiara along with 2 other guys were reincarnated, gaining powers when they arrived. Kiara could force people to do what she said and abused it to control people and get what she wanted. When various factions oppose the 3, one of the guys is killed and another is nearly defeated before retreating. The remaining guy returns to Kiara and Kiara thinks the 2 guys had won. The guy explains the situation before strangling Kiara to death and absorbing her to gain more power.