Only Nuka ever fully understood exactly why he called Kovu a termite. Everyone else just saw the nickname as a label Nuka used to express his annoyance towards his adopted younger brother. Perhaps it was because they perceived Nuka as a mangy, useless, and relatively stupid waste of space, but his pride could never understand all of his thoughts. Nuka might not appear bright, but even he can show a flash or two of intelligence once in a while. It's a shame nobody ever thought twice about the young lion's intelligence.
Being unable to rid his fur of the pests himself, Nuka knows exactly what he's talking about when he refers to Kovu by his nickname. Those pesky parasites have infested his fur ever since he was a cub after all. Though the rest of his pride dwells in the same termite mounds as him, only Nuka seems to constantly attract their builders. Nobody understands exactly quite how annoying they are like Nuka does. Sure, they might seem relatively intelligent and mildly intriguing to the others thanks to their massive homes and complex societies, but Nuka sees their darker side.
It is true that Nuka didn't mind Kovu's existence at first. He even enjoyed his adopted brother back before he was named the chosen one. Nuka absolutely loved having someone younger than him besides Vitani to boss around. Besides, who could ever even consider hating such a cute little cub? However, like a termite egg ready to hatch, Kovu was something small and seemingly innocent bound to bring trouble eventually.
The moment Scar declared that Kovu would take Nuka's place as the chosen one, Nuka's attitude towards his brother rapidly changed. What Nuka had once considered cute and cuddly became nothing short of a nuisance. Kovu was still just a baby termite back then. He was not yet old enough to pose too many problems for his foster brother. Though Scar began pretending that his son never existed almost immediately, Zira's attitude changed at a slower pace. She did spend more time with Kovu, but she did not neglect Nuka. She made sure he was fed and occasionally smiled at him when he managed to make a kill. But Kovu was clearly becoming her favorite. Zira was always singing to him, telling him stories, and cuddling with him. It seemed to Nuka that his parents didn't love him anymore. That little termite might as well start trying to suck Nuka's blood while he was at it. Little did Nuka know that things would only get worse from there.
Things went downhill quickly after Simba's take over. He banished Zira, her family, and her followers not long after defeating his uncle. Though Nuka was secretly glad that his father had died, he knew he would have to struggle even more to stay alive. As time passed, he got even scrawnier and his mane became terribly shaggy. As he had predicted, the Outlands had little food, water, or even shelter. Everyone had to settle for carrion, murky puddles, and, of course, the termite mounds. That wasn't the worst part for Nuka though. He had still been the third highest member of the pride when it had prospered, but now even Vitani outranked him. Instead of hunting, Nuka was forced to watch Vitani and Kovu every single day. That only fouled his mood even further. The happy cubs reminded him of the life he had left behind. His mother only ever looked at him with distaste and anger thanks to the environment shortening her temper. And what a temper it was. If Kovu even looked like he'd gotten dirty under Nuka's watch, he had to suffer through horrifying screaming sessions and beatings. This was around the time Nuka first began to consider Kovu a termite. As the actual creatures sucked his blood and made his itch constantly, so did Kovu seem to become more unbearable by the second. Nuka was not foolish enough to ham the chosen one physically though. He resorted to scowls, glares, the silent treatment, and even occasionally leaving the cubs on their own when nobody was looking to prove his point.
One such instance led Kovu to encounter Kiara. Nuka thought Zira would kill him when she came home, but he was more than thrilled to hear Kovu take responsibility for once. To Nuka's frustration, the cub's brief scolding ended only in a plan. Thanks to his little foster brother's irritating exploration, the cub was to begin rigorous training with Zira to prepare for a plot against Simba. In the following years, Nuka rarely saw his mother. Though this meant he didn't have to endure any more punishments, he still felt his hatred for Kovu grow. That tiny termite was rapidly growing by sucking Zira's attention away from Nuka. After Kovu left the pride as a young adult, Nuka still suspected it would only be a matter of time before that darn termite returned to a hero's welcome. Who knew the lion Nuka called a termite could spread his very own plague that only seemed to kill Nuka's spirit.
The last time Nuka saw the termite, he wasn't so little anymore. Even though he was just a young adult, Kovu dwarfed the adult Nuka. As Nuka and the rest of his pride perused Simba, Nuka feared that the pest would finally claim the glory that should have been his. But the termite refused. He actually wanted to help the enemy. Now was his chance! Nuka took the opportunity to chase Simba himself. Kovu the termite had just squashed his chosen status. Maybe there was still hope after all! But no, that was not meant to be. As Nuka finally grabbed Simba's paw, he heard a loud crunch. The next thing he knew, he was tumbling down the log pile. He landed with a thud and screamed as he realized he was trapped with nothing but more logs to look forward to.
As Zira frantically tried to save her only son, Nuka managed a tiny smile as he died. Sure he would never see Simba die, but he had still accomplished his mission. The termite was squashed and so the love that it had held so long finally gushed out in time for Nuka to see it as he left. Though Nuka had no way of really knowing the fate of the termite, he was glad to finally be rid of the pest once more. His hate had gone unhitched for years and being able to scratch it at last, even if only for a moment, was ecstasy.