Etam

Etam is a character with a long, convulted history.

If you look at my other characters and worlds, you'll see the KAS Project group, where the description mentions how those characters were originally from a Kirby sprite comic known as Kirby Adventure. In that comic, I would occasionally, rarely involve myself within the story, as a form of stereotypical "Authorsona". Since my username at the time was Ultimate Yoshi, I didn't want to represent myself in-comic as a Yoshi, so instead I went with a green Kirby wearing a blue cap, based on the Yo-Yo Kirby copy ability.

Partways through the comic, in about 2013, I decided I would briefly embrace the trope-y nature of my authorsona and similar other trends from sprite comics online, and indulge a bit in a "for-fun" sequence involving an "Anti-Author" sona character. I inverted the sprite sheet of my Ultimate Kirby character, fixed up the subsequent shading, and dubbed the resulting pink Kirby with a tan hat "Ybrik Etamitlu" in an obvious backwards-naming scheme. Since my username would often be shortened from Ultimate Yoshi to just Ulti, I decided to shorten Ybrik Etamitlu's name into just Etam.

The resulting segment of the comic, "Tear in the Fabric", was short-lived, and involved Etam popping into the comic and messing with the reality of the comic and the characters' personalities for a brief period, before my own authorsona popped in and "defeated" him. It was brief and reception was mixed, but Etam was on his own popular enough. He would later cameo in a fellow Kirby sprite comic author's webcomic, Kirby's Dream Adventure, which much more heavily involved an authorsona of the creator. 

It was those cameos in KDA that led me to wind up redesigning Etam later down the line in 2015, when I initially changed my username from Ultimate Yoshi to Ultizeta and gave myself the blue lizard sona that most people now know me as. While Etam never had a corresponding Yoshisona to go along with Ultimate Yoshi, I decided it would be fitting for him to get a lizardsona to match my new lizardsona. Instead of inverting the blue lizard, I decided to keep the pink coloration and the tan hat, and transform the Kirby directly into a lizard. I also renamed him, similar to how I gave myself a new username. Thus, instead of being Ybrik Etamitlu, his new name became simply Etamanti.

Over time, Etam's lizard design changed alongside my own lizard design, and he has frequently been a reflection of myself. While not necessarily exactly an "evil opposite" like the trope typically would wind up going with, I tend to think of Etam moreso as myself without inhibitions. He's confident as opposed to my anxiousness, he's proud rather than self-conscious, he's dominant rather than submissive, he's snarky without fearing what others might think of him. He says what he wants and does what he wants simply without worries, rather than having zero morals and being an actual bad person. Obnoxious? Probably, but not actually awful.

He also somewhat retains a bit more of a tongue-in-cheek, fourth-wall-breaking understanding of his nature, even as a lizard. He's fully aware of the meta role that he plays, and won't hesitate to directly point things out about the medium in which he's being presented in, or talking directly to people behind their screens. Admittedly that could be a make-or-break part of his characterization, but it's such an ingrained aspect of the original idea that I didn't want to remove it from him when updating his design.

BASICALLY, TL;DR:
Etam is a separate, individual form of my sona without inhibitions that could be somewhat dubiously claimed as an "evil" opposite. He's meta and snarky and likes to show off.