According to Shinya in SHOXX #96, he and Kyo (京) met for the first time when Kyo came to watch Shinya's session band (name unknown, Vo. Unknown / Gt. #4 / Gt. SHIGE / Ba. KISAKI / Dr. Shinya) in August 1995.
In the same magazine, Shinya mentions that he and Die met for the first time when Ruby and Ka・za・ri performed at the same live in September.
Toshiya and the future members of Dir en grey meet for the first time when he comes to greet La:Sadie's after their live.
DIR EN GREY (ディル アン グレイ) officially forms.
The name is a combination of German "dir", French "en" and English "grey" and, according to an interview in Apres Guerre #19 (March 1997), was thought to mean "Grey Silver Coin" (灰色の銀貨 Haiiro no Ginka). It was supposed to convey a music and an image that wasn't caught by neither black or white, so they picked "grey".
Interestingly, there's a demo tape released in 1995 by the visual-kei band LAREINE, one of the songs on that tape is called "Dir en gray". It opens with the line "灰色のあなたに dir en gray" (Haiiro no anata ni dir en gray), which both means "To you in gray" and would actually fit the intended meaning of the words, as opposed to "Grey Silver Coin". In the aforementioned interview, Kyo also mentions that he knew that phrase before, so Lareine's song is most likely the source for Dir en grey's band name. Why they thought that "dir" means "silver coin" remains unclear, but they would later become aware of their mistake.
In turn, Lareine got the name "Dir en gray" from a band called Dir & Gray, a visual-kei band that was active around 1991. The original meaning behind the name was "dill of grey colour" (dill is usually white) and was coined by guitarist SHOW. Interestingly, their name was written with the same Katakana as Dir En Grey, ディル・アン・グレイ, even though "and" would be written as アンド (ando) in Japanese.
According to Toshiya on the radio show Nack5 FM Triangle Super Audition, one of the other names the members had in mind was Kisaragi. It was taken from a high school band of Toshiya.
V. Kyo (京) / G. Kaoru (薫) / G. Die / B. Toshiya / D. Shinya
Event tour 覇叉羅 presents JENOSIDE ZONE vol.5 starts. Dir en grey participates in secret.
Event tour 覇叉羅 presents JENOSIDE ZONE vol.5 ends.
Event CLUB CITTA' Kawasaki Shusai EVENT (クラブチッタ川崎主催イベント) takes place. Dir en grey participates in secret.
Event HYPER MIX takes place. Dir en grey participates in secret.
Kessei Kinen ONEMAN LIVE (結成記念ワンマンライブ) takes place as Dir en grey's first official live.
Event NEO Behind the Mask takes place. Dir en grey participates in secret.
Two-days ONEMAN LIVE (ワンマンライブ) takes place. Dir en grey gives out a special message tape at each show.
Instore event at Osaka DEAD ONE.
Instore event at Kyoto JEUGIA Sanjo Main Store.
Instore event at Osaka Like an Edison.
Instore event at Shibuya Indies House.
Instore event at Harajuku ROCK LOVE.
Event tour 8 BEAT GAG Sokan Kinen Ranbu LIVE SHOCK WAVE' 97 vol.2 (8ビート・ギャグ創刊記念ライブ SHOCK WAVE' 97 vol.2) starts.
Instore event at Osaka JEEZ Shinsabashi Store.
Instore event at Osaka Miyako Shinsaibashi Store M-Cube.
Instore event at Tokyo Shinseido Quartier 5 Shinjuku Store.
Two-venues ALBUM 「MISSA」 Hatsubai Kinen 2Days (アルバム「MISSA」発売記念2Days) takes place to commemerate the release of Dir en grey's first mini-album MISSA.
Instore event at Shinjuku Teito Musen.
Event Neo Behind the Mask takes place.
Event Behind the Mask takes place. Because this date is not listed in the band's timeline on their OHP, it's possible that they did not perform.
Four-days, three-venues live Dir en grey Presents MAZOHYST OF DECADENCE SHOW starts.
Event tour 8 BEAT GAG Sokan Kinen Ranbu LIVE SHOCK WAVE' 97 vol.2 (8ビート・ギャグ創刊記念ライブ SHOCK WAVE' 97 vol.2) ends.
Four-days, three-venues live Dir en grey Presents MAZOHYST OF DECADENCE SHOW ends.
Event EXPERIENCE EYES '97 takes place.
Two-days live CRUCIFY OF MARIA ・・・TO “MISSA” Anata no "Biteki・Hatsujou・Ka" o yobiokosu (CRUCIFY OF MARIA ・・・TO “MISSA” あなたの『美的・発情・香』を呼び起こす) takes place.
Oneman 「楓」~if trans・・・~ Mechanism For Leave-sin- takes place.
Tour 「楓」~if trans・・・~ Mechanism For Leave-the scene of the tragedy- starts.
Tour 「楓」~if trans・・・~ Mechanism For Leave-the scene of the tragedy- ends.
Event tour SHOCK WAVE'98 vol.1 ~春の嵐~ starts.
Event tour SHOCK WAVE'98 vol.1 ~春の嵐~ ends.
「Kaede」~if trans・・・~ Mechanism For Leave-Unknown・・・Despair・・・a Lost- ~裁きの血舞台~ takes place.
GRADATION sponsored event 「A Birth Day」 takes place.
Two-days live ~in the secret cradle~Routokage to Garasubachi (~in the secret cradle~蝋蜥蜴と硝子蜂) takes place on August 3 and 4.
a knot Hossoku Kinen EVENT Dir en grey in OKINAWA (a knot発足記念イベント Dir en grey in OKINAWA) takes place over the course of three days, with a live on day two.
TOUR Deep [sink], Deep [gaze], Deep [agonize], Deep [-] starts.
TOUR Deep [sink], Deep [gaze], Deep [agonize], Deep [-] ends.
Tour final TOUR Deep [sink], Deep [gaze], Deep [agonize], Deep [-] Final More Deep [sympathy]~meet evil with evil~ takes place.
-「a knot」 only- live PSYCHONNECT~Arashi no Mae no Bousou~ (PSYCHONNECT~嵐の前の暴走~) takes place.
Tour PSYCHONNECT -mode of “GAUZE”?- starts.
Event SUPER LIVE'99 in TOKUSHIMA takes place.
Tour PSYCHONNECT -mode of “GAUZE”?- ends with a secret live.
-「a knot」 only- event Dir en grey YELLOW SPECIAL EVENT takes place.
-「a knot」 only- event Shiwasu no Yoru ni Ashiyon no Jigatame!? (師走の夜に足四の字固め!?) takes place.
Three-days event Dir en grey EXPRESS PREFESTIVAL TOUR 1999 takes place from December 16 to 18. No lives are held.
Tour final 本当にこれでいいんですね ハイ あなたは何人目ですか 一人目です 僕は数え切れない子供を殺しています あなたは許せますか ・・・・・ もう一度聞きます 本当にこれでいいんですね ハイ 用意はいいですか ハイ では始めましょう takes place.
TOUR 2000 The type of Deity starts.
TOUR 2000 The type of Deity ends.
Event Fujikyu Presents SOUND CONIFER 229 SHAKE the BLACK 2000 takes place.
TOUR 00⏩01 MACABRE brain gain(er) brain drain(er) starts. After the first live, Kyo suffers from sudden hearing loss and the rest of the tour is postponed to 2001.
TOUR 00⏩01 MACABRE Deep [-], Deep [-], Deep [-], Deep [er] starts.
After this live, Kyo suffers from an acute acoustic trauma in his left ear and the lives scheduled for December 18 and 21 are postponed to 2001.
TOUR 00⏩01 MACABRE Deep [-], Deep [-], Deep [-], Deep [er] ends with a secret live.
TOUR 00⏩01 MACABRE brain gain(er) brain drain(er) restarts.
September 13, 2000, replacement live.
September 14, 2000, replacement live.
September 19, 2000, replacement live.
October 28, 2000, replacement live.
October 29, 2000, replacement live.
September 23, 2000, replacement live.
September 26, 2000, replacement live.
September 28, 2000, replacement live.
November 2, 2000, replacement live.
October 4, 2000, replacement live.
October 2, 2000, replacement live.
October 1, 2000, replacement live.
-「a knot」only- event FAN CLUB 「a knot」 Gentei CLUB EVENT (ファンクラブ 「a knot」限定 クラブイベント) takes place as the December 21, 2000, replacement live.
October 24, 2000, replacement live.
October 25, 2000, replacement live.
September 20, 2000, replacement live.
-「a knot」only- event FAN CLUB 「a knot」 Gentei CLUB EVENT (ファンクラブ 「a knot」限定 クラブイベント) takes place as the December 18, 2000, replacement live.
October 11, 2000, replacement live.
October 10, 2000, replacement live.
October 18, 2000, replacement live.
October 15, 2000, replacement live.
October 17, 2000, replacement live.
October 13, 2000, replacement live.
September 22, 2000, replacement live.
September 16, 2000, replacement live.
TOUR 00⏩01 MACABRE brain gain(er) brain drain(er) ends with a September 17, 2000, replacement live.
TOUR 00⏩01 MACABRE FINAL More Deep【quake】 takes place.
Three-days live Souten no Hekireki (蒼天の霹靂) takes place.
After changing the notation of their band name to DIR EN GREY on Ryoujoku no Ame in July 2006, but then briefly reverting to Dir en grey on Agitated Screams of Maggots in November 2006, the band permanently changes it to allcaps with the release of THE MARROW OF A BONE in February 2007.
Two-days oneman UROBOROS –with the proof in the name of living・・・- takes place.
Tour IN THE DYING MOMENTS starts.
Tour IN THE DYING MOMENTS ends.
TOUR2012 IN SITU starts.
TOUR2012 IN SITU ends.
TOUR16-17 FROM DEPRESSION TO ____ [mode of UROBOROS] starts.
TOUR16-17 FROM DEPRESSION TO ____ [mode of UROBOROS] ends.
Two-days event ANDROGYNOS with PIERROT takes place.
Event Free-Will SLUM takes place.
TOUR19 The Insulated World starts.
ALBUM Release Commemoration LIVE takes place to celebrate the release of The Insulated World.
TOUR19 The Insulated World ends.
TOUR19 This Way to Self-Destruction starts.
TOUR19 This Way to Self-Destruction ends.
Event The World You Live In takes place and is livestreamed on the band's YouTube channel.
I think this is pure speculation and maybe the comment section here is not the best place for rumours (a forum would be better...), but they seem to get along just fine, certainly better than the years they were struggling to break overseas in 2005 or 2006. I believe there is an old post on DYNAMITE TOMMY's blog or some sort of fan club magazine mentioning how Kyo almost left the band around that time (I might be wrong because this was 5000 years ago)...
They've probably had their ups and downs over the years. You can't expect people to work together for so long and not have a few falling outs. I remember there being a period around the Uroboros and Arche era where Kyo apparently didn't know where anyone but Shinya lived, but I think that's long gone now. Ever since their new album came out, they seem to have rekindled their friendships and interact with eachother way more than they used to, and have way more synergy as a band