Wuju Devoured
Wuju Style:
Bonus True damage: 10 / 15 / 20 / 25 / 30 (+ 10 / 12.5 / 15 / 17.5 / 20% AD)
Assuming full build
We're looking at around 256 before counting runes/masteries.
We're also assuming max attack speed of 2.5
If we give Yi a double strike proc and phantom proc on his first attack, we're looking at 244 true damage.
Second strike would be 80.
Third would be 160.
80
244
ect.
At this rate, to deal even 1K true damage he would need a minimum of 7 auto attacks which means nearly three seconds to deal just 1K true damage. The only way for Yi to cut this time down is through Challenging smite or ignite, which shaves off about a second, but still leaves Yi having to auto you for two solid seconds for him to really deal a lot of damage.
My point. It's not the true damage killing you, it's his magic damage and crits....