To call Arthur eccentric would be being kind. He has about as many idiosyncrasies as Earth has ants. There's nothing Arthur does that he doesn't have rules for, that he doesn't have to do in a certain way at a certain time or place. It isn't that he believes the whole world could explode if he doesn't do these things at these certain times or places, he just assumes the world could explode if he doesn't do these things at these certain times or places. One of the most prominent things noticed about Arthur is his fantastic ability to be having a completely rational conversation with you and then suddenly go off in a fit of complaints or rages about irrational things, like why is the sky blue when it could be pink, and why do we worry only about planting trees when bushes and plants create oxygen too. His emotions change swiftly and suddenly, like a car accident. Another trait to note is his complete and total disregard for the feelings and privacy of others, even though he keeps himself very private and does not like others diving into his personal affairs. Arthur does not seem to realize the effects his actions and words can have to others.

If Arthur is good for anything, it's for a good laugh. Whether you're laughing at him or at something he's said, and he tends to say funny things without actually meaning for it to be funny, he's easy to laugh around. Some would think that being in the presence as someone as peculiar as him would make one tense or awkward, but he is so odd that it's hard to not make yourself comfortable with him. Though at times he can come off as very childish, such as barely being able to take care of himself, or needing things to be his way. He may come off as being very random, jumping from subject to subject as quickly as one blinks, but in some way they all connect in his brain and it's perfectly rational to be talking about feminism and monkeys at the same time, which some might find more offensive that others.

Arthur is always right. It doesn't matter if you have facts and and references and he's one against hundred, he is always right. That is not to say he does not like to discuss controversial topics or hear others opinions on certain matters, on the contrary, Arthur loves to tell his own opinion so he has gotten used to hearing others. Though if someone tries to deny his opinion, he can become very upset and irritable, which leads him to usually not do well with others. Overall, Arthur is very much like a incredibly well-informed child, which knowledge beyond his years but he highly lacks the social skills to do much but shut himself up in his home and write.

Appearance
5'9" 1/2 and slimly built, Arthur is not very strong physically but relies on his brains instead. Typically he wears suits when out in public, and sweatpants when at home. Unless he's had a very bad week writing, then his appearance may consist of things thrown together haphazardly, and definitely do not match. The majority of his suits very clearly used to be very expensive, but years of wearing them and his inability to iron them makes them loose and crinkled, but it fits the writer-look.