Senna, while being a fairly new Champion, is someone who has been in and out of the meta around a million times now. Senna's constant fluctuating in and out of the meta, is almost certainly due to her Passive and how it interacts with minions. When Senna was released she was either going to be a full time Support or a full time ADC; however, players who played her realized that Senna was hyperbusted and could dominate anyone in the Bottom Lane. Slowly people started to realize that Senna was best suited to be an ADC, as she was capable of outputting insane amounts of damage. This, and the fact that Senna was being played basically every game in both solo queue and pro play, made Riot decide that she needed a nerf. This nerf hit Senna's ability to generate stacks for her passive. No longer would Senna be able to farm minions and scale with her passive as well as she used to, since Riot changed the drop rate on souls that Senna could harvest from minions she killed.

Not being able to properly farm now, players found a loophole in Riot's Nerf. This loophole was the fact that Senna now could harvest way more Souls if she was played as a Support. This was because Senna’s Soul drop rate didn’t change on minions she didn’t kill, and it didn’t change how she interacted with other Champions and obtaining their Souls. From this loophole, Fasting Senna was born - a Senna designed to carry games through the Support Role. However, it appears as if Riot is back-tracking their nerf and trying to push Senna back into a more active ADC role, with her most recent buff in Patch 10.12. In Patch 10.12, Senna had her passive nerfs reversed and buffed, as her Soul drop rate went from 1.67% to a whopping 8.33% on minions she kills. Originally Senna’s soul drop rate was 5.55% meaning, not only did this recent change in Patch 10.12 make her Soul drop rate astronomically better than before, this Patch also made her better than when she first was released.

Now that the history of Senna and why this Patch is so astounding has been discussed, lets discuss the new build path on her and why you should try it out.

First and foremost, these are the Runes you should be running on Senna, as they mesh well with her Kit and allow her to thrive in League of Legends better. The main difference in Runes is that this Senna doesn't go Glacial Augment, but instead goes Undying as it meshes perfectly with her Kit, and allows her to gain more Health and survivability once the late game hits. For those wondering, Senna still receives slows with this build. However, instead of the Slow coming from Runes, it comes from her items.

Main Runes:

Grasp of the Undying: Every 4 seconds in combat, your next basic attack on a Champion will – Deal bonus Magic damage equal to 4% of your max health – Heals you for 2% of your max health – Permanently increase your health by 5. (Ranged Champions: Damage, Healing, and permanent health gained reduced by 40%)

Font of Life: Impairing the movement of an enemy Marks them for 4 seconds. Ally Champions who attack Marked enemies heal for 5+1% of your max health over 2 seconds.

Bone Plating: After taking damage from an enemy champion, the next 3 attacks or spells you receive from them deal 30-60 less damage.

Overgrowth: Absorb life essence from Monsters or enemy Minions that die near you, permanently gaining 3 maximum health for every 8. When you absorb 120 Monster or enemy Minions, gain an additional 3.5% maximum health.

Secondary Tree:

Presence of Mind: Takedowns restore 20% of your maximum Mana or energy and increase your maximum Mana by 100 (up to 500) or your maximum Energy by 10 (up to 50)

Legend Alacrity: Gain 3% attack speed plus an additional 1.5% for every Legend Stack (max 10 Stacks). Earn progress towards Legend Stacks for every Champion Takedown, Epic Monster Takedown, Large Monster kill, and Minion kill.

Secondly, the items that Senna builds are all designed to work around the Runes previously mentioned. Along with aligning the Runes and Items, these Items are arguably the best Items on Senna, as they solve her Health problem.

Lane:

Doran’s Blade (DB)/Shield (DS) (depending on Enemy Lane) (Cost:450): (DS) - +80 Health, Restores 6 Health every 5 seconds, Basic attacks deal an additional 5 Physical damage to Minions on hit. Unique: Regenerate up to 40 Health over 8 seconds after taking damage from an enemy Champion, based on percent missing Health. (DB) - +8 Attack Damage, +80 Heatlh, +3% Life Steal.

Core: (Ideal Itemization Order)

Frozen Mallet (Cost:3100): +700 Health, +30 Attack Damage – Unique Passive: Icy: Basic Attacks slow the target's Movement Speed for 1.5 seconds on hit (40% Slow for Melee Attacks, 20% Slow for Ranged Attacks)

Black Cleaver (Cost: 3000): Dealing Physical Damage to an enemy Champion reduces their Armor. - +400 Health, +40 Attack Damage, +20% Cooldown Reduction.

Boots of Swiftness (Preferred Boots but Build Boots around enemy team) (Cost:600): Enhances Movement speed and reduces the Effect of Slows - +60 Movement Speed, Unique Passive – Slow Resist: Movement Slowing Effects are reduced by 25%.

Edge of Night (Cost: 2900): Periodically blocks enemy Abilities. - +325 Health, +55 Attack Damage – Unique Passive: +10 Lethality.

Infinity Edge (Cost: 3400): Massively enhances Critical Strikes. +80 Attack Damage, +25% Critical Strike Chance.

Overall, with this latest Patch, Senna has become S-Tier in the bot lane again and is going to be played a lot more as an ADC due to the fact that she can harvest Souls on her own. However, Fasting Senna is still extremely strong and can still generate more Souls than ADC Senna, but now ADC Senna can catch up in the Mid-game, and so it is up to you to decide which Senna you wish to play.