The reasons behind Yi being absolutely nuts currently

Okay, okay, to give you some math on why his double strike passive is actually bonkers...

Pretty common Yi items to have together right? Well, when Yi's Double Strike hits with these it does the following:

2 Auto Attacks (Physical) 2 hits of Bloodrazor for 8% current HP (Physical) 2 hits of BorK for 16% current HP (Physical) 2 Hits of Guinsoo's Rageblade passive (Magical) 2 Hits of Wuju Style (True)

BUT WAIT THERE'S MORE

Guinsoo's Phantom Strike GUARANTEED kicks in for another

1 Hit of Bloodrazor 1 Hit of BorK 1 Hit of Rageblade 1 Hit of Wuju Style

In total your looking at 36% HP damage along with on-hit magic and true damage that actually is close to 200 each.

This isn't even including the Alpha Strike damage he just did to get to you, or the BorK active that hit you for another 10% HP.

Did I mention he has Conquerer to convert more of this to True Damage?

This is off just the FIRST of his AAs against you, assuming he charged his double strike up. He likely has well above 2.0 AS too, soooo, welcome to the slam. No champion needs to do this much damage based on items alone. It's overloaded.