I actually wouldn't recommend Ashe. She is very squishy and has no real escape mechanism unless you know how to kite.

I'd say Ryze maybe. He can be built tanky and still dish out some dmg. And he has his root to protect himself. Anyone with a stun might work as well, Taric or Sion. They are also tanky, Taric has heals and Sion has a shield.
Anything that would protect him from a gank.

Ashe, Xin Zhou, YI, Veigar(if you read spells b4 you use champions)

Morgana, Ryze, Rumble,

Yi, 1 click kills

Master Yi.

nunu

Soraka. Heal allies. Restore mana to allies. Win game.

Meanwhile, friend will be learning valuable lessons about watching the map. (R)

Ryze.

Support for someone bad seems wrong to me, you need to be able to rely on support.

You don't need to rely on a bad carry, you just carry harder.

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