Yuri is 5 years old. He is smart, independent and happy, and has a very fertile imagination. He is an only child, and as a result is sometimes lonely, and can be a little selfish.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...