Best Champions for ranked play/smurf play

Hello all. I would like to know the best champion to use in ranked play for season 5. I would also like to know the best champion for smurfing because my friend recently started playing and I don't want him against silverish players. Don't recommened champs that you saw a player get 30+ kills like once. Again this is very optional and only for those willing to give me some of their time. Thank you and GLHF all =D.