All Takafumi's party member that had the romantic indication died, no wonder he's lonely till the end. All that's left after his party member died is cunning women who want his children as a soldiers and political tools.
Consider what they were doing with Scott's mom I wouldn't be remised if she did the darkest of arts to pump that essence into a manakin or something more tangible. Also yeah as a Yandere enjoyer... Even I know that it's best in fiction. Dealing with a real one... My body goes numb.