For Odin I don't think it's a matter of not taking damage, you have to actively be parrying him in order to prevent his Zantetsuken I think.
Staying long range doesn't help since he can still damage your teammates.
I don't know for sure if that's how it works, since I never beat him flawlessly. I somehow managed to tank Zantetsuken and finished him off afterward.
I don't kill... but I don't lose either.