Tsundere

 is a Japanese term for a character development process that depicts a character with a personality who is initially cold, temperamental, hotheaded (and sometimes even hostile) before gradually showing a warmer, friendlier side over time.
The word is derived from the terms ('to turn away in disgust or anger') and ('to become affectionate'). Originally found in Japanese bishōjo games, the word is now part of the otaku moe phenomenon, reaching into other media such as maid cafés, anime, manga, novels, and even mass media. The term was made popular in the visual novel "Kimi ga Nozomu Eien".
Terminology.
Manga author Ken Akamatsu lists "tsundere" as one of the special cases in his definition of "moe": "The person feeling it must be stronger: The object of 'moe' is weak and dependent (like a child) on the person, or is in a situation where she cannot oppose (like a maid)... (*Tsundere only: There will be times where the stronger and weaker role is reversed)." The concept has received increasing attention in Japan, with a maid cafe named Nagomi in Akihabara started having "tsundere" events in 2006 and "tsundere"-themed products released (like Tomy Co.'s portable television set), and the concept increasingly reflected in recent anime, from an extended discussion of the meaning of the concept and its origin on the Internet in "Lucky Star" Lucky Channel segment classifying the characters according to "tsundere"-ness. Another accepted definition of "tsundere" is a girl or a guy who has a combative attitude toward others but is also kind on the inside. They usually play out as having an attitude toward the main character, either a male or a female, and often criticizing them in one way or another, until they eventually warm up to them or fall in love with them as the series progresses, though they usually find it very hard to admit it or outright deny it in some cases.
Comiket organizer Koichi Ichikawa has described Lum Invader of "Urusei Yatsura" as being both the source of "moe" and the first "tsundere"; figurine sculptor Bome has also cited Lum as an inspiration for his designs. Manga critic Jason Thompson named Madoka Ayukawa of the 1980s series "Kimagure Orange Road" as the root of the tsundere archetype. Other anime and manga featuring "tsundere" include "Love Hina", "Neon Genesis Evangelion", and "Bakemonogatari", among many others. Some voice actors have garnered a reputation for voicing "tsundere" characters such as Rie Kugimiya who voices Louise in "The Familiar of Zero" and Nagi in "Hayate the Combat Butler". In "Excel Saga" volume 15, author Rikdo Koshi defines "tsundere" as "hard on the outside, soft on the inside" and associates it with character Misaki Matsuya.
"Tsundere" as a concept is not strictly limited to women, and is not strictly limited to manga or anime. The character from the series "" is portrayed as being "tsundere", and is paired with a "lovable loser", . "Tsundere" role-play has become a common theme in maid cafés.