Introduction

This guide is currently a work in progress. However, you can still gain a lot of value from the information below. There's much confusion in the community as to her build right now. It sort of goes against everything that Senna has ever wanted to do in the past. I promise you though, this is the best you're going to get for Senna in 11.2, and it's not even close to other builds.

Why Guinsoo's Rageblade Over Infinity Edge?

• Much higher burst than IE at ALL stages of the game. (auto > q > auto combo)
• Slightly better sustained damage (repetitive auto attacks) then Infinity Edge in the early game with low critical hit. Significantly higher than Infinity Edge's sustained damage auto attacks in mid and late game.
• 600g Cheaper than Infinity Edge.
• Scales Infinitely with the critical hit coming from her passive.

tldr; There is no point in ever building Infinity Edge. It doesn't provide you with anything more than Guinsoo's Rageblade, at any point in the game.

Senna automatically receives -14% crit damage from her passive. This automatically makes Senna a less effective critical hit utilizer.

Her Q does not critically strike, however it does apply on-hit damage. When you auto attack to harvest a soul, you are attacking as usual and applying on-hit damage, plus harvesting the soul applies an additional proc of on-hit damage. She then has every third auto attack doubling on-hit damage from Guinsoo's passive, making her apply a total of 5 on-hit procs from Guinsoo's Rageblade when she uses her auto > q > auto combo.

Additionally, what most people are talking about is the fact that Guinsoo's on-hit damage scales infinitely with her soul passive. You get 100% crit chance from your build, as well as additional critical from your souls harvested, which can continue to stack infinitely as her souls build up.

The only current unintentional bug with Senna and Guinsoo's is that Riot intended champions such as Senna and Tryndamere to overcap Guinsoo's on-hit damage with the additional critical chance they can achieve beyond 100% (or 120% if you sell boots) with their passives. However, they intended that to cap out at 200%. Currently Senna can continue to convert critical hit in to Guinsoo's on-hit damage infinitely. This build will lose absolutely zero value if Riot decides to fix that bug, though. No game should last that long. You've already won the game by then, if you're getting that big.

Even without auto > q > auto and in scenarios where you are straight auto attacking; Guinsoo's Rageblade still out damages Infinity Edge on Senna with zero souls; it’s very close damage to IE early on, but it’s also significantly cheaper than IE. So it should be noted that no matter how many souls you have, rather you are trying to burst, or auto attack someone to death, Guinsoo's will always do more damage than Infinity Edge.