Info;

BASIC INFORMATION
Name: Cassius
Aliases/titles: Agent Cassius, The Traveler, Chowhound (by Ilsa)
Age: Appears late 20's to early 30's, but he has implied that he's older than he looks. Headcanon says about 50.
Canon Point: Flexible, but after Home Sweet Moon preferred.
Race: Moondweller (classified as "Other" in-game)
Element/specialty: Dark, fire and water, with melee and spear proficiency.
FIRST IMPRESSIONS
Appearance: Pale, abnormally so. His skin has a grayish tinge to it, which is a trait other moondwellers both from the moon and born in the Sky Realm share, either due to genetics or the conditions on the moon, even both in some cases. The most color he has are the color of his eyes, and the red liner underneath.
Fashion: Typical moondweller clothing seem to be robes and armor with a futuristic aesthetic, leaning towards freedom of movement rather than protection. He will always, always bare his chest no matter what though-- it seems to be a common fashion choice among moondwellers.
Height: 183cm, or approx 6'0.05".
Build: Tall and lean, but with decent musculature that's most obvious with his overly defined chest. He definitely made gains by fighting and working, and not being a regular at the gym. Some of his build may be influenced by being a moondweller, as they're all well-built either by genetics or augments, and everyone has very prominent chests.
Hair: A very pale grey-blond, very long and straight. It seems to be the exact same hue as his skin. Sometimes he puts it up in a tail, but Cassius prefers to let it fly free.
Eyes: A blue-green (electric blue?) that's unnatural for other races but shared by all moondwellers. There are rings in his eyes that look like camera lenses (maybe they actually are lenses?).
Voice: His voice actor is Masaya Matsukaze. He's husky and breathy, and rarely raises his voice.
Language: The skydweller common language, and moondweller speech. Moondwellers communicate via electronic sounds (which are transcribed as nonsensical anagrams in the EN script, and in katakana-based cyphers in the JP script).
Scent: Sometimes sugary, depending on what he's been eating recently.
Hand dominance: Ambidextrous. But he clearly prefers using his right hand for battle.
Literacy: He can read and write, but don't expect anything legible out of a man who grew up around computer systems.
Triggers: Cassius does not register emotions, thoughts, physical pain or memories the same way we do, and despite going through terrible things for a year, he's not at all bothered by any of that. He might not have triggers at all, considering his actions at the end of Home Sweet Moon/Stay Moon, though he may trigger other people instead by joking about the terrible things that have happened to him.
Other: Parts of his body have been augmented/replaced by cybernetics, though it's not immediately obvious. His digestive system and parts of his brain are confirmed to have been enhanced or replaced via moondweller technology (making him able to digest weird shit like glass, and store memories like someone stores and saves files into a computer). As such, Cassius will be affected if an EMP or anything similar is set off near him, with the exception of signal jammers.