Yup, this is correct.

Only ninja with the taitou symbol near their name will be immune to debuffs and get that 20% increase

Thanks for the info :)

This is why, if you want root of the warrior, sasuke is normally included in the team.

I would want him but the enemy mostly does is that they go for a Sasuke first because he's a bit squishy. Even me, if i would spot a Sasuke in the enemy's team i would go for him first.

Sasuke's only purpose, for me at least, is to do is buff and increase damage even further in the first few rounds that you're immune.

If you're looking for other taitou ninja that would work well, try using Kimmimaro, who's a good tank, or Orochimaru, who has pretty awesome overall stats.

Hidan or Kisame are also sword- bearing ninja. As is Suigetsu.

If you're going to use Root of Warrior, I'd suggest getting Jugo, as he'd buff and and provide a shield for Kimmimaro and Sasuke (and any other cursed mark characters)