Halo Infinite spoiler
First, the color :
Bungie said Cortana was purple when she was young, they show her as purple in Halo Reach and Halo CE. Then 343 made Halo CE anniversary and decide to represent her in blue. Then 343 made her purple in Halo Infinite. Where is the logic ? This is non-sense !
I understand they wanted to differentiate her from “the weapon”, but they should have chosen another color instead of purple
Now, the story :
Cortana died in Halo 4, it was beautiful, she get a cool end. Rebring her to life to turn her evil was a huge mistake. She wasn’t even the Cortana we known and loved, she was just a fragment corrupted by the Domain who didn’t deserved to be called Cortana.
The worst, off course, was to kill her off screen. Despite her omnipotence, she was killed easily and quickly. A so important character deserved a better end. 343 try to give her a sort of redemption by her sacrifice, but there was nothing heroic in her last moment because she already knew she was convicted. Worst, her sacrifice don’t change anything since Atriox has survived.
343 kill Cortana, turn her evil, then kill her off screen and even replace her by another Cortana. Never a loved character have been so mistreated!