When Kiara was born, the Pride Lands were restored to their former glory, the hyenas were expelled from the territory and Scar was dead; but once again, nothing lasts forever. Certainly not for Simba; when he was a child, he felt that when he was king, then he could do whatever he wanted. As an adult, reality took out a crowbar and started beating him with it; or at least, the ghost of Scar took out a crowbar and started beating him with it.

This was evidenced by the new king becoming much more protective of his daughter to the point of being overprotective of her; indeed, the influence of Scar was felt across a region outside the Pridelands. Let's call them the Outlands, because that was their name. Within these outlands was a certain pride who saw Scar in the same way as the Pridelanders saw Mufasa: They saw Scar as a God. And the head of this...cult...wanted to avenge his demise.

We call our supporter, "Zira". A fitting name, since her name translates to "hatred" and "hatred" was the one emotion she felt towards the Pride Lands; towards her youngest son, Kovu, she did the same thing to him as Scar's influence had done to Simba: Took out a crowbar and beat every ounce of compassion and innocence that he may have had as a child, with that crowbar. Unlike Simba, it never worked because Kovu tried to prove that he was nothing like the God that Zira and her pride still worshiped...to no avail.

But Zira's hatred was ultimately her undoing because she was blinded by hatred towards the Pridelanders that she saw no reason; having lost one child, she threatened to kill her own daughter, Vitani, who wanted a truce and it was this that caused Zira to lose her own pride. And, her own life; during a fight with Simba's daughter, Scar's devoted supporter committed suicide by letting herself fall off a cliff and into a dam, despite Kiara's attempts to save her.

With Zira's demise, Scar's legacy was gone forever; his cult dissolved itself and joined the Pride Lands and Kovu found himself becoming a part in the royal family of the Pride Lands while Vitani became the leader of the so called Lion Guard, a team of animals whose duty was to protect the Pride Lands and the Circle of Life. Though I suppose you could say that because Kovu would eventually take over from Simba as ruler of the Pride Lands, Zira succeeded in fulfilling Scar's wish; just not in the way she hoped.