{Exquisite Blood}
{Sanguine Bond}
These two together.
What happens when you either gain life or opponent loses life:)
Would it trigger back and forth killing opponent?
Yes, it's an infinite loop.
However it an infinate loop that wins the game, not an infinate loop that stops the game as a tie. Correct?
Correct. Your opponent can't lose more life than he/she has, so once at zero you no longer have a valid target for {Sanguine Bond} and thus the loop stops.
Awesome combo though
I'd like to see the ruling as I don't think it's instantaneous. You gain life triggering one blood that then goes on the stack. Once that resolves your opponent loses life, which triggers the other blood and goes on the stack. Once that resolves you gain life ant the process loops from there. You are free to respond to the triggers at any time by whatever means you have. Once your opponent reaches 0 life, they lose the game as a state based action, which is why the game doesn't end in a draw with the infinite loop. If there were an effect in play that prevented your opponent from losing or preventing you from winning, the loop would become infinite and you would draw.
Yeah, it would trigger back and worth:) but yes it can be countered:)
Good combo though