Well in terms of Ignis why he only lost his sight compared to Nyx loosing his life we can see it has something to do with how much power they accessed from the ring. When Ignis looses his sight in the regular path he is able to fight Ardyn but he obviously was still not really a match for him so he only barely accessed the rings full power, in the alternate path for Ignis to use more of the rings power he has to sacrifice his life and we see his entire body is getting destroyed, and he managed to temporarily defeat Ardyn, he only survived cause Noctis asked the crystal to save him. As for Nyx when he used the ring he went ape shit and practically used Knights of the Round against diamond weapon and was teleporting and fighting in the air all DBZ style so he died since he used so much of the rings power. Plus as we could see the ring is kinda picky, in Kings glaive we saw Ravus only lost his arm, while that other dude got completely fucked after putting the ring. So in conclusion the kings are just dicks.
Last edited by RespectDecena - on 28 March 2018