He is a Beorn and his skin tone is grey. He wears a dark black robe with a big A on it. His eyes, nose, and mouth are all red and he wears gloves. His shoes are black and pointy and his ears are longer and sharper than a regular Beorn.
Lord Acriss was raised with one lesson in mind: only the cruel survive. Years of abuse had been tied to him, slowly breaking his mind in the process. At first, he seems very cocky and confindent in his abilities. Eventually, though, he breaks free of his shell, and becomes a monster, furious and filled to the brim with hatred for humanity. He's stated that the "A" on his stomach is where his heart was located.
As Unten heads towards the drill that's drilling Zeon's crust and soon core, Acriss appears and manages to trap Unten in a cave. As Unten fights him, parts of him fly off, revealing that he is somewhat of a cyborg. As Unten defeats him, it is revealed that that Acriss was just a shell for RAMiranda, who's AI has evolved to the point where it has crossed into a spiritual level. As thousands of dark spirits of dead Beorns appear, Unten manages to scare them off with a couple of quick, erratic sparks and escape from the cave as "The Darkness" spread across the land, looking for hosts to add to RAMiranda's hivemind, now known as The Darkness.
Unten has no time to deal with them and Acriss is nothing but an empty husk now, although parts of his mind live on in The Darkness, silenced by RAMiranda.
Originally in the original pitch for the character Acriss had a final form: Giga.
When he is Giga, he is a giant black Beorn with horn-shaped ears and fangs. He has gears sticking out of his body and blood-red eyes, nose, and mouth. He also sends Pitch Blacks of Unten, Spunten, Mario, Yoshi's, Fruity, McBoo, Kenny Koopa, etc. He has lost his legs and now has a genie-like tail and his hands now have claws. He speaks in a distorted voice and chases his opponents.
This form served as inspiration for his role in Tragedy, which is yet to be revealed.
In an interview with Acriss' creator, he stated that Acriss is in one of four timelines.
The first one is where Acriss is born into a normal family and becomes the hero. (The Unten Timeline.)
The second one is where Acriss is still born in the same family, but is the younger and less noticed brother, (The Spunten Timeline.)
The third one, in which he's born into an abusive family, and becomes the normal Acriss we all know. (The Lord Acriss Timeline.)
The final one is where Acriss is born into the same normal family, but as a female Beorn. (The Bearlina Timeline.)
Using the information he gave, people have concluded that Unten, Acriss, and these unknown "Spunten" and "Bearlina" character are the same character, just in different timelines.