I just realized that Khalil -- one of my newest OCs -- will be five years old this year. (STOP IT, TIME!) So, I made a character progression/character development timeline for him.

Created: June 2015
When I first designed him for DA's dis-colour roleplay, he had an older look to him despite being on the upper end of 14 years old. Left is a frame from my first comic for that RP group. At right is the pic I used for his RP tracker, drawn shortly after I started becoming active in the group.

2016: dis-colour route 2
As it often happens with my characters, as I continued to draw him, Khalil's features softened up. The shape of his eyes also shifted, and he started getting his own nuanced expressions (like that low-key smile pictured at left and his infamous grumpy cat face -- more on that later). Pictured at right is my first go at coloring him traditionally. The other characters pictured are Charlotte and Ira, owned by Bashful-cupcake and TadakoNanako, respectively.
Over the course of the RP, Khalil also had a lot of character development writing-wise, much of it tied to him learning to open up to people again through his two friends/surrogate family pictured in the right-hand artwork.

2017: Prismatic Haven
I bailed on dis-colour after route 2 and moved Khalil to a similarly-themed but more light-hearted roleplay group set up by another former member of D-C. Prismatic Haven was a short-lived RP, but it was fun putting Khalil into more slice-of-life situations.

2018
One of said slice-of-life situations pictured: Khalil and Nellie, my other OC for Prismatic, don't get along. Back in an older picture, toyotami kun said that Khalil's expression looked like a grumpy cat. That impression stuck and became his trademark irritated face. In P-H, "Mr. grumpy-cat face" even became his nickname (courtesy of Nellie). XD
After both RP groups closed, I continued to write about Khalil in crossovers and offshoot stories (though neither of them have yet to see the light of day).

2019
In '18 and '19, I started adjusting his facial features again. In my head, I always thought of him with a wider nose, but I didn't start off drawing him that way. So, he's got a wider and rounder nose in his current look. The pic at right is a scene from the aforementioned crossover story.