These four terms are all part of the otaku "moe" phenomenon that has been growing in popularity these past few years, and in particular are called "gap-moe" traits.
Moe is a hard word to define, but it embodies the feeling of attraction or cuteness in a character or even a person.
Gap-moe is a particular type of moe which derives its value from a "gap" in the character's personality. The 4 examples here are considered a type of gap-moe because of the stark contrast between the dere side and their other half.
Dere|Deck is more than just a playing card deck. It is the beginning of a move towards moe in the west. Each suit is represented by a personification of a dere type (tsundere, kuudere, yandere, dandere) in the form of these girls.
The Cards
The deck consists of 54 cards - 4 suits of 13 and 2 jokers. The 3 face cards of each suit are full detailed illustrations of each girl representing the suit. For example in the Tsundere suit, the K, Q, J shows a custom tsun-tsun, tsundere, and dere-dere illustration of the girl in that order. The Ace card has a special design and the 2-10 will show her expression and body pose ranging from tsun-tsun to dere-dere.
Our amazing artists!
We have many artists to thank for their crucial help, but these 4 are playing a key role in developing the artwork and designs for the four girls. Each artist has taken on the role of one girl, one type of dere, and will be illustrating that suit.
Rosuuri.Tsundere: A freelance illustrator and comic artist who specializes in multimedia arts and web interface designs.
.Tsundere
: A freelance illustrator and comic artist who specializes in multimedia arts and web interface designs. 
Inma.Yandere: Illustrator and mangaka who has produced many doujinshi and original works. She has also worked on many book and game illustrations.
.Yandere
: Illustrator and mangaka who has produced many doujinshi and original works. She has also worked on many book and game illustrations. 
Blizz-Mii.Dandere: Specializing in UX design, front-end development, and illustrations, she is an entrepreneur who brings in experience from working both in Japan and in the US.
.Dandere
: Specializing in UX design, front-end development, and illustrations, she is an entrepreneur who brings in experience from working both in Japan and in the US. 
Ai-Wa.Kuudere: A lover of illustrations and fan art, she is a professional at crafting characters and is part of the Spanish Doujin circle CYCLIC★REDUNDANCY.
.Kuudere
: A lover of illustrations and fan art, she is a professional at crafting characters and is part of the Spanish Doujin circle CYCLIC★REDUNDANCY.
