I feel that this is leading to an ending where he really is insane.
...Like think about it, fantasy waifu suddenly shows up outta nowhere, magical healing spider, writing in a journal.. like who the fuck writes in a journal nowadays?!
FUCKING FINALLLYYYY....
Though I must say, for a fight that drawn out, the ending was a bit anti-climatic. But I guess it just goes to show how all that regard that the demon had in her own power was a waste compared to our Freiren-sama.