Because in every training session, Gamora could easily defeat Nebula. Thanos therefore clearly valued Gamora more.
And it was more than just a little favoritism; he valued her greatly.
Nearly everything Thanos considered best was given to Gamora. As for Nebula—
not only did she not have Thanos's affection, but Thanos had also dismantled her body.
She had been turned into her current mechanical form.
Now, it seemed the only thing Nebula could still use was her head—and only half of it at that.
That was undeniably far too cruel for Nebula.
Because of this, Nebula had always been desperate to prove herself, to prove that she was no worse than her sister Gamora.
She wanted Thanos to look at her more, and she also wanted to surpass her sister.
Nebula worked harder than anyone else.
She was also more loyal to Thanos than anyone else. Nebula would not allow anyone to sully her father's name.
Especially when those people were her father's subordinates, Nebula found it even more intolerable.
Thinking of this, Nebula's tone toward Ebony Maw and the others grew sterner. "Do you think Father is someone you can casually judge?"
"Or do each of you think you've become so capable that you no longer need Father's discipline?"
Nebula crossed her arms and looked righteously at the Black Order.
This displeased the Black Order.
If the one reprimanding them now had been Gamora, they would surely have listened seriously and respectfully.
After all, Gamora was someone who could speak in front of Thanos.
But the one reprimanding them now was Nebula, a daughter of Thanos in name only, whose status was even lower than theirs.
That made them unhappy.
But since they were indeed in the wrong and should not have discussed Thanos behind his back, they did