Iām about to say f**k it and let it go
Let me explain 174
Nephyths saw the mirror that Seth gave her. She saw Osiris' reflection on it but Osiris didn't see her so Nepthyths was the only one affected by the mirror's function.
Due to the mirror's effect, when she met Osiris, she asked him for a child. Osiris basically manipulated her so that she won't tell Seth a thing about Anubis not being Seth's actual son.
Since this is Isis going in a flashback of memories, she bursted at Sehkmet; blaming her for the situation. Which to Sehkmet replied that it was Osiris' plan all along, all she did was make sure it didn't go according to his plan. It was later revealed that the war was caused by Osiris and not by the Sun God, but Isis kept playing oblivious.
In short, Nephyths really loved Seth but due to her seeing Osiris on the mirror, the mirror replaced her memories of Seth and replaced it with Osiris, Osiris started the war over the mirror. Isis know all along what Osiris was planning to do to Seth using the mirror.
(English is not my first language, sorry for the errors ><)
Yall my head hurts trying to understand this did we skip a chapter? 174?