Like her sisters, Diku seems to be passive and doesn't stand up for herself when Scar takes the pride, though she does congratulate her sister for standing up against Scar.
King of the Jungle
January 1990 version
In The Lion King written by J.T. Allen, Mufasa, Zazu, Simba, and Nala watch as Sarabi, Naanda, and other lionesses hunt down a zebra. Along with Diku and Dwala, the lionesses successfully pin down a zebra. Sometime later, Diku scolds an adolescent Simba when he ruins one of the lionesses' hunts. After Banagi talks Scar into becoming the king, Scar and the hyenas march to Pride Rock, and overwhelm Mufasa who charges at them, while the lionesses look on helplessly. During Scar's reign, the lionesses are harassed by the hyenas to continue hunting despite the shortage of food.
When Simba returns and defeats Scar, the lionesses look down on Banagi and Baasho before Simba decides to banish them to the desert.
May 1990 version
In King of the Beasts written by Allen and Ron Bass, Diku sits alongside her sisters and Simba as Mufasa watches a fire raging near the border of their lands. When all options fail, Mufasa gives a signal to Sarabi to run, and the lionesses and the animals of the kingdom flee. Next, when Simba and Nala are adolescents, Diku is implied to be hunting with the lionesses. Soon after, she and the lionesses gather to see Mufasa challenge Scar in a duel at the fire tree bridge. After Mufasa loses and dies, Scar and the hyenas ascend to power with Simba running away into exile.
At a waterhole, Diku tells a frustrated Nala that it was "simply delicious" how she stood up for herself against Scar. Then, Nala decides to form a false interest in Scar in order to turn him against the hyenas, and it's implied that Diku disapproves of this idea. After Simba returns and defeats Scar and the hyenas, the lionesses look on with tears in their eyes. Finally, Diku stretches along with her sisters and niece like "Egyptian goddesses" across the kopje, watching the herd graze fully healthy again.