Three moe romance herione types.
The "dere" means "lovestruck". Prefixed with each of "tsun", "yan" and "kuu", they indicate a character's displayed and hidden personalities.
Can be aloof or argumentative (tsun tsun) at first, warms up to the love interest later on. Rie Kugimiya is the voice of tsundere. Examples include Aisaka Taiga from Toradora.
Has appeal due to the general childishness, the cute denials of love, plus the sense of progress and accomplishment once they start to go "dere". Also good for comedy.
From "yanderu", sickness. The usual displayed trait is "dere", but over time, the character can develop possessive tendencies and other love-related mental illnesses, usually resulting in the death of the competitor. Examples include Gasai Yuno from Mirai Nikki.
Has appeal due to the absolute dedication and willingness to go to extraordinary lengths for love. The fact that "dere" is present from the start is good for the impatient, and yandere behaviour increases the dramatic content of any story.
"Kuu" is, essentially, "cool". An emotionless character, often socially isolated, eventually opens up to the love interest. Extreme example of introversion, requires patience just like a tsundere, but more suited to those who find loud characters annoying. Examples include Tachibana Kanade from Angel Beats.
Has appeal due to the general childishness, the cute cluelessness about love, and again the sense of progress and accomplishment.
I appreciate all three character types myself, but amongst those I know, I am associated with my yandere fandom.
How about you? What do you think of these -dere types?