Q: What are the full names/full Japanese names of the characters?

A:  Table taken (with permission) from checkmate:

 

Japanese (In Japanese order if a Japanese name)	English (In Western order)
Mutou Yuugi	Yugi Moto
"Yami Yuugi" (unofficial)*	Yami
Mutou Sugoroku	Solomon Moto
Mazaki Anzu	Téa Gardner
Honda Hiroto	Tristan Taylor
Jounouchi Katsuya	Joey Wheeler
Kawai Shizuka	Serenity Wheeler
Bakura Ryou	Bakura
Kaiba Seto	Seto Kaiba
Kaiba Mokuba	Mokuba Kaiba
Pegasus J. Crawford	Maximillion Pegasus
Cyndia	Cecilia Pegasus
Malik Ishtar	Marik Ishtar
Isis Ishtar	Ishizu Ishtar
Rishid	Odion
Kujaku Mai	Mai Valentine
Otogi Ryuuji	Duke Devlin
Kajiki Ryouta	Mako Tsunami
"Dinosaur" Ryuuzaki	Rex Raptor
"Insector" Haga	Weevil Underwood
"Bandit" Keith Howard	Bandit Keith
"Ghost" Kotsuzuka	Bones
Pandora	Arkana

*This name is an invention of Japanese fandom. He is not EVER called Yami in either the Japanese anime or manga. The characters refer to him as 'Mou Hitori no Yuugi' and he is listed in the info book as 'Yami Yuugi' His actual name is until very late in the manga, unknown-- the whole point of his participation in Battle City is so he can find out what it is, along with all his other memories.  In the video game 'Forbidden Memories' he is given the name 'Bel Um Fel/Fet' but it's not canon for the series. 

Q: What do the characters' names look like in Japanese?/What are the kanji for the characters' names?

A: 
Q: But I saw it spelled Mariku/Marik, can't it be spelled that way?

A: Because of how the Japanese language is, there can be differences in rominazation. Malik is an Egyptian name, and when it's written in Japanese, it becomes Mariku.  Marik is an improper combination of the pair.
 

Q: Isn't Marik/Mariku/Yarik/Yalik the name of Yami Malik?

A: No. Yami Malik's only name is Yami Malik. He's often refereed to as 'Malik no yami no jinkaku' (Malik's dark personality) by the cast (mostly Isis and Rishid) or by just Malik.
 

Q: But Shizuka's Jounouchi's sister. Why isn't her last name Jounouchi as well?

A: Their parents were divorced. One assumes her mother either remarried or went back to using her maiden name, and Shizuka's name followed.
 

Q: What are the names for the Memory World / Ancient Egyptian versions of the characters?

A:

Modern day character	Ancient Egyptian version
Yami Yuugi	Pharaoh Atemu
Kaiba Seto	Priest Set *
Yami Bakura	Thief King Bakura-sama**

*  The name is romanized Seto, but Set is the name of an Egyptian God, and is what the name Seto was based on, according to an interview with the manga's creator. Set can also be written as Seth but the h is silent.

** This is what he refers to himself as. Others refer to him as just 'Bakura'

 
Q: I've seen the term 'Hikari' used for the non yami halves of the characters. What does that mean/is that correct?

A: Hikari is a term meaning 'light' which is a US fan-term.  None of the characters use this term.
 

Q: So then what's the 'correct' term?

A: The Japanese fan-term (and the term most often used in the show) is 'Omote' which means surface, front, face, exterior or outside. In the series, Malik refers to nomad Bakura as 'Omote no Bakura.' Almost everyone calls Yami Yuugi Mou Hitori no Yuugi.
 

Q: What do the yami and omote haves refer to each other as?

A: Yuugi calls Yami Yuugi 'Mou Hitori no Boku' ['The other me'].  Yami Yuugi calls Yuugi 'Aibou' [Partner]  Yami Bakura calls Bakura 'Yadonushi' [Host or Landlord] and Bakura doesn't really refer to his yami. The most he does is referring to him as 'koe' ['a voice'].
 

Q: Who's that red haired woman in the hospital alongside Yuugi's grandpa? Is that his mother?

A: Yes. She's listed in the guide book as 'Yuugi Mama' and has brief appearances in the anime and manga.
 

Q: Does Yuugi have a dad?

A: Neither the manga or anime show Yuugi's dad and he is never mentioned.  In an interview, Takahashi comented that Yuugi's dad is away on work.
 

Q: Do you get to see any of the rest of the cast's families?

A: You briefly see the boots of Jounouchi's father and hear him cursing in manga volume 2, and see his mother in the anime, and Shizuka, his sister, is a character in the Battle City and Battle Ship arc.  You also see Honda's nephew, Georgie, in manga 4, and his dog, Blankey in volume 16.  Otogi's dad is shown in volume 16, and Kaiba's adopted father, Gozaburo Kaiba is mentioned in various places in the anime and manga.  Also, in the anime, Bakura's father is mentioned and shown briefly. 
 

Q: I heard that Kaiba killed his father. Is that true?

A: No. Kaiba indirectly caused the death of his adopted father, but did not actually kill him. When Kaiba took over Kaiba Corp., Gozaburo jumped out of a window.

 
Q: I heard that Shizuka won Kaiba over with a song and they're dating. Is that true?

A: No. There is barely any interaction between these two characters in the anime and none at all in the manga.  In the anime, their only interaction was when Shizuka asked Kaiba to stop the Duel Ship after the first battle to get medical help for Bakura. Kaiba didn't and instead had a doctor sent to Bakura's room. There was no song and there was no date.
 

Q: Are any of the characters dating/couples?

A: No. The closest you get to established couples are just implied. Yuugi has a crush on Anzu and Jounouchi likes Mai, but they're far from being couples.
 

Q: Is Kaiba really older then the rest of the cast?

A: No. Kaiba is in the same grade as Yuugi and the rest of his group. They're all in their 2nd year of high school. 
 

Q: How old is everyone in the show?

A: Yuugi, Anzu, Jounouchi, Honda, Bakura, Otogi and Kaiba are all in their 2nd year of high school [no exact age is given].  It should be noted that Japanese high schools are different than American high schools, and 2nd year there is the equivalent of 11th grade here, making the characters around 16 or 17.   Sugoroku is 72, Mokuba's age isn't listed, but in the manga, it was said he was born when Kaiba was 5, which makes him 11 or 12, assuming Kaiba is 16 or 17,  Mai is 24, Kajiki is 19, Haga is 14, Esper Roba is 17, Ryuuzaki is 15, Bandit Keith is 26, Pegasus is 24, Malik is 16, Isis is 20,  and Shadi's is unknown. Rishid's age, while not listed or stated outright, can be figured from the flashback in manga volume 24. He was 4 years old when he overheard the Ishtar parents talking, and a year later, Isis was born.  Malik is 16, therefore Rishid is 25. 
 

Q: What is [characters name]'s birthday?

A: 

Yuugi: 6/4 Jounouchi: 1/25 Anzu: 8/18 Honda: 4/19 Bakura: 9/2 Otogi: 2/28 Kaiba: 10/25 Mokuba: 7/7 Mai: 11/20 Kajiki: 3/1

Haga: 7/21 Roba: 4/1 Ryuuzaki: 12/29 Bandit Keith: 8/12 Pegasus: 10/8 Malik: 12/23 Isis: 4/5 Rishid: Unlisted/Unknown Shadi: Unknown

All dates are listed American order with month first, then day.
 

Q: There's all these fanfics where the yami and omote halfs are in separate bodies. Does that ever happen?

A: No. The closest they come is where Yami Yuugi or Yuugi stand next to the other in a shadowy form. They have never been shown to both be physical/solid at the same time.
 

Q: Why does Yugi suddenly grow when he's inhabited by the spirit of the Millennium Puzzle?

A: He doesn't. When his yami takes over, he stands differently, giving the illusion that he is taller, and the anime tends to exaggerate this. Yuugi and his yami are the same height.

 
Q: Is there any evidence in the manga/Japanese version that Yami Bakura abuses his host?

A: Not really. There are two instances where Yami Bakura harms the body he's residing in in the manga, once in the Monster World arc, and once in the Battle City arc.  In the Monster World arc, he impales his hand on one of the towers of the castle because Bakura had been controlling it to help Yuugi and everyone fight his yami.  In Battle City, he plunges a knife into his arm as answer to Malik's question if he will work with him or not, then retreats back into the Ring telling Malik he can 'borrow his host for a while.' There it seem his aim is not so much to abuse Bakura, as it is to use his pain to further his goals. [It can be argued that in the set up for the Monster World arc, there is another instance in the part where the Ring's pendants have embedded themselves in Bakura's chest, but it doesn't seem to pain Bakura at all and is quickly forgotten in light of other events.] 
 

Q: Is Bakura an albino?

A: No. Albino have no colour to their skin or hair and their eyes are red from a similar lack of colour. Bakura has brown eyes and his skin, while pale, has colour to it. And while there are forms of albinism where the person does have colouration, an albino will almost always have poor eyesight, be sensitive to brightness and will need glasses. Bakura has never been shown any of these characteristics.  Judging by the variety of naturaly impossable hair and eye colours in the anime, it is safe to assume there is no medical cause for the conditions.
 
 

Q: When did the stuff in the past actually happen? 3,000 or 5,000 years ago?

A: The first installment of the manga listed it as 5000 years ago, but it was changed to the more accurate 3,000 years ago very soon in. The dub never picked up on this change, and kept it at 5,000 years ago, which places it in the wrong historical time peroid.
 

Q: If Yami Malik came from the Rod and Kaiba's past self had the Rod, does that mean Yami Malik's Kaiba's past self?

A: No. Yami Malik was born from Malik's pain and hatred and never lived in ancient Egypt.