I hit a losing streak of 15 at about level 20. I had a positive k/d almost every game, and I had just purchased kennen. So my most played list has kennen with 2 wins and 14 losses, but a normal k/d ratio. I switched to someone else and started winning, anyone else and I got a win, I had a ten game winning streak, switched back to kennen for a game and lost it.

I can't pick him without losing I think.

i had a winning streak, 10 wins over with yi (this was back when i was a noob)

then i lost..and lost..and lost and got 20 loses under

then it became steady after that

Longest for me was 17. I hated life. It was insane. Felt like quitting.

I went on a 13 game losing streak right after a patch...

My longest was 6. but then again my longest win was 9. Can't seem to get over +50.