Niko Rin and Alice are all have a somewhat Tsundere behavior.
Niko is strict, intelligent, cultured and speaks very well. She is also formal and a bit old schooled and doesn't understand technology sometimes.
Rin is trendy, absent minded, playful, a bit clumsy and weird but she's a good cook and uses the word "like" in her speech.
Alice is a rude know it all and the biggest Tsundere of the three she's also bossy and overprotective. She's also negative and nags alot but she's still kind deep down