Back when The Lion King 2: Simba's Pride first went into production, the various animators and story writers began to work on the characters. In the final version of the film, Kovu is not the son of Scar, and was simply adopted. This, however, was not true at first.
When Disney first put the film into production, Kovu was actually supposed to be Scar's son and heir.
However, they eventually realised that it would cause a slightly disturbing problem within the film's plot.
As you know, during the film, Kovu falls in love with Kiara, who is the daughter of Simba.....who happens to be Scar's nephew. Thus, this would have made Simba and Kovu cousins, as well as Kiara his second cousin. This would have caused incest. So, the concept was dropped.
In response, the animators were forced to alter Kovu's design, so he would not resemble Scar so it was believable that they were unrelated. However, they did keep a few similarities.
This is my version of Kovu if they kept Scar as Kovu's son. x3 I made him more Outlander-like than the official Kovu, especially since he looked nothing like Zira or Scar. I gave him freckles, since Nuka and Vitani had them, and I just felt he needed something more. I also gave him Zira's chin fur, instead of Scar's goatee.
I based him more off of his concept art before the change was made: http://www.lionking.org/~vakasi/concept/24.jpg
But I did keep his tuft so he still seems like Kovu, but I made it less poofy.
Rused background and shading xD' didn't even try with it.