Do you have a source for this?
I don't recall with any certainty. I'm a big fan of mythology and have studied a lot of it*. Most of it was picking up all sorts of odd books or coming across strangle articles, the stranger, the better. The pope who declared that to deny the existence of werewolves as heresy(which was reversed by the next pope) was one of those fun articles I enjoyed. I know some of... well, a LOT of mythology that wasn't extensively documented at the time gets all kind of really passionate arguments for various interpretations and original sources.
*Global myths, not just European. Too many people only think of Greek/Roman stuff when they think of mythology at all.
Just so much of that entire chapter was great, but this part in particular is a delightfully inspired form of evil. The confusion will be glorious. And probably also the swearing.
Remember, Kabuto always bows out before the final round. He's done it 6 times, I think, as of Naruto's first exam, always getting to the end, but then 'suffering such horrible luck' leading him to withdraw over and over. If he'd wanted to be promoted, in canon, he could have insisted that he was great support via being a good medic, and just less of a direct combat specialist. All it would take to make him a perfectly fine chunin, even at the time of the invasion, and only showing what he actually did in canon, would be to ensure he was always paired with strong combatants who weren't good enough tactically for leadership roles.
Seriously, no more than four rounds of elimination, at most, twice a year(and only when its at an ally you trust your shinobi to be vulnerable around) is the source for all promotions to chunin? Bull. Getting seven teams though to the final stage shows his ability every bit as much as, possibly more than, how he fights in an arena, with an audience.
