Did Ultear know there was a different way to defeat master Hades? In episode 116 after Ultear lost the fight with Gray, she tells him that he cannot beat Hades, but does not tell him anything about Hades' weakness (eg: his heart).



This seems weird since when she had Zeref a couple episodes back, she was about to stab Hades in the back and take Zeref for her own purposes. This would imply that she was no longer on Hades' side.

Later we see that the guards knew that the room Hades' was in was something they could not lose control of.



Since the guards knew about this wouldn't Ultear know this as too, seeing as she was pretty much raised by Hades?
Urtear did know for sure. She had been trying to deceive Gray all along. She told Gray that the Iced Shell was the only way because the spell traps the caster as a shell of ice for all eternity. She wanted him to die because she thought Gray was the one responsible for her mother not loving her which was not true at all.

Urtear knew more about Hades than any of the outsiders. She obviously had a plan to kill Hades herself but having Gray kill him would be killing two birds with a single stone.

But Gray realizes that after he over hears her and sees her trying to kill Juvia.