This is a Tier List of the items relevant to a Support Senna. Item's not in the chart aren't even worth considering nor will they have any explanation provided in the following section.

BORK is one of the strongest items on Senna. The stats and passive are both almost perfect. If you build this item, it'll be the most noticable power spike in the match. The synergy with Senna's A+Q+A combo and her ability to apply this damage safely at range are the reasons it's stands out so much.

Umbral Glaive is a fairly weak item on it's own but the utility and the very low cost make it a compelling pick up. After some testing, I found that the pairing of large amounts of lethality and an Armor Penetration item like Lord Dominik's Regards result in a massive amount of damage. Up until recently, I believed BORK+LDR was the best 2-item spike for Senna but now I know that Umbral+LDR is better due to being 1000g cheaper and dealing similar damage with more utility.

Due to Senna's free damage on her passive and to a lesser degree the AD she gets from collecting souls (which is only a bit more than you'd get from actually having base ad growth) as well as Blade of the Ruined King's on-hit damage, Armor Penetration is extremely effective on her. Since Senna has a really really low base hp, she is an ideal user of LDR. LDR's passive gives her bonus damage against just about every single champion in the game and the full 25% against bruisers and tanks (where as most would only see the full amount against tanks). Naturally, build Mortal Reminder instead if the enemy team has significant sources of healing.

With the buffs to Inifinity Edge and Senna now dealing 75% Crit Damage (just like everyone else), this item is quite compelling for both support and ADC. Currently, Senna has no good mythic. This is still the case. IE is strong but only marginally better than Youmuu's against squishies and marginally weaker than Eclipse against tanks. This is my current default mythic. I recommend this item unless the enemy team has multiple tanks - in which case, go Eclipse.

This is one of the best mythics on Senna at this time. The stats are average and the passive is not going to blow your mind (you can thank Graves for this item being undertuned for ranged) but the Armor Penetration mythic passive makes up for all these deficiencies. 4% Armor Penetration per legendary is 12% Armor Pen which is quite nice. Also the movement speed from the item passive helps with repositioning after you complete your burst damage rotation. I recommend this item when going into teams with more than one tank or a very impactful (fed) tank. The damage to squishy champs is pretty much even with Youmuu's Ghostblade so you don't miss out on anything except that item's mobility.

Ghostblade is the preferred mythic on Senna at the moment. It's pretty much tied with Eclipse for damage (a bit more vs squishies, a bit less vs tanks) but the movement passive and active effects are a very welcome addition. Also the 7 Attack Damage per legendary mythic passive is one of the best parts. Build this by default unless the enemy team has many tanks or highly relevant tanks.

This item is very popular in high elo. When paired with Blade of the Ruined King you get to deal decent damage while also having some durability. Additionally, the passive and active on the item give your team some durability which as a support can be important. You can find success with this in low elo but you are also leaving damage on the table to help your team. It is dependent on your team picking team fights with you there to reach it's potential as well as having a competent damage source in your team. Two things that aren't a given.

This item is a good alternative to Lord Dominik's Regards when the enemy team has significant sources of healing. This includes champions like Soraka, Aatrox, Red Kayn and Irelia to name a few. I would recommend Lord Dominik's Regards over this item when dealing with self-healing tank champions like Dr. Mundo and Nasus since the bonus damage exceeds the value of the anti-heal. Dr. Mundo will full heal off ult whether you have Grievous Wounds on him or not.

This is a very strong item against heavy armor tanks. Champions like Malphite and Rammus make this practically a must buy. Senna is one of the very few supports in the game that can afford to build this and it's not even bad on her. You can stack it up pretty quickly with your existing rotation (say it with me now Q+A+W+A) and within seconds everyone is ignoring 30% of the target's armor. It's a devastating blow especially since it also reduces the damage that Malphite and Rammus do since their damage scales off armor and instead of penetrating it, you're removing it altogether. Other match ups that call for this item are ones where the enemy team has a split pusher that's applying lots of pressure. Since you can buy both an armor pen item and Black Cleaver you end up getting past about 50% of their armor. With this you can often counter a split pusher alone if you avoid their ranged skillshots.

I used to favour Wit's End over this item when dealing with heavy magic damage sources but since then I've concluded that Wit's End's focus on sustained damage (attack speed and on-hit passive) and reduced magic resist and attack damage make it less effective compared to this item's ***ping 65 AD, 50 MR and massive magic damage shield that can allow you to survive combos that nothing else would. As a bonus, this item is quite cheap to buy as well. Compared to this, I would never recommend Wit's End unless their entire team is magic damage. In that scenario, Wit's End would replace Blade of the Ruined King in your build.

Maw's armor cousin, this item is built under similar circumstances - the enemy team has a lot of phyiscal damage threats. Even then, you need to do the math on if the loss of damage from getting this item over it's competition is worth the investment. If it's a hyper fed AD Shaco, odds are this item won't stop him from one-shotting you anyway so better to deliver more damage in fights and hope your team picks off the Shaco after you're dead. You'll note that Guardian Angel is not on this item list. I never build it and find it very hard to recommend an item with a safe-from-death passive that'll get used once in a match and probably won't be useful when it does go off. Hopefully Riot makes GA's passive an active one day so that it can be used with intent and be a source of skill expression.

While it may seem a counter intuitive pick for a Support to take this item, it actually performs decently well in PvP and can assist your team to maintain lane pressure in a siege. Firstly, the stats are quite good - a bit heavy on Attack Speed but still ok. It's safe to ignore this item as a support but it's worth noting it's existence and usefulness in particular situations.

As your last item, this is a compelling option. At this point in the game, you should have 80-90% Critical Strike Chance exclusively from your passive and the 20% you get from your chosen armor penetration item. This item will get you to that 100% you want and maybe even give you some extra life steal. At any rate, the main draw of this item is the lethality. Now that you have a lethality mythic and an armor pen item, lethality is your primary source of damage output amplification in the game. There are other items with 18 lethality but the full package with this item just edges them out in my opinion.

This is a viable alternative to Lord Dominik's Regards and Mortal Reminder in the case where the enemy team has no tanks and very little healing. The passive on this item is practically useless but the extra Attack Damage and the Ability Haste it has make it attractive since both are top tier stats on Senna (especially after you anyway have 100% crit chance from your passive). The safer option is to buy Lord Dominik's Regards but you can also opt for this and get good results.

This item is very strong on Senna due to her ability to pop out attacks and abilities and her synergy with raw AD as a stat. The reason it's this low in the tier list is that getting this item is an ordeal and a half. Senna is one of the slowest Tear of the Goddess stackers in the game and since this item would be best as a last-item, she doens't have any inventory slots to build any other components of the item. Maybe if you're ahead and know you won't need that extra power for a while you can afford to invest in the future so to speak but I can't actually recommend building this on Support Senna. Hopefully one day Riot will make a mana mythic for Attack Damage champs and then this item could become more appealing. Senna, Blue Kayn and Ezreal would all love that.

Another good last item option, this item balances raw hp for durability and top tier raw AD for damage scaling but the most appealing part is the passive. Since Senna's AD is almost entirely Bonus AD, she gets good value from the passive compared to other ranged champions. This item will end up giving 40+ ability haste total on Piercing Darkness and Curse of the Black Mist and 30+ ability haste total on her Last Embrace.

A weaker 4th item contender, this item still has some synergy with Senna's kit due to her A+Q+A combo triggering it quickly but its recent changes to be Phyiscal Damage instead of True Damage as well as the scaling being changed from Bonus AD to Total AD make it much weaker than before. I don't recommend building this unless the enemy team has 3+ tanks and you're building around sustained damage output (at which point you're pretty much doing the ADC build instead of the Support build anyway).

This item is tempting since it provides more safety for Senna than any other item in the game. The extra 150 range means at you have the same attack range as towers if you build it first item and the 7% movement speed is also very impactful. Not only that but Kircheis Shard will surprise you with how strong a first-back it gives. If it's so good, why don't I recommend it? The main reason is that the stats are trash. Also it promotes playing from afar which means you aren't in range to use Last Embrace you have to step up to engage after using it and it allows you to stop learning good positioning which is an essential skill when playing Senna.

Given the fairly unexciting landscape of Senna mythics, this one stands out as one that'll get your blood pumping. The synergy with Piercing Darkness's on-hit and the cooldown reduction you already get on it each time you attack means you get only a second or two cooldown on the ability. Unfortunately, despite this, the item underperforms on damage when part of a full build and forces you to build a mana item (e.g. Manamune/ Muramana) to sustain your mana levels. Even if you came up with a solid build using this item, it would require 2 or 3 full items before it came online and no one can wait that long (especially not a support) to be relevant.

Decent item, fairly inexpensive but also not really strong. I wouldn't build this unless the enemy team had massive shield threats. Only Sett, Ivern, Tahm Kench and maybe Dr. Mundo would make me consider building this. Even then you'll probably get more value building more damage.

This is a Tier List of the items relevant to a ADC Senna. Item's not in the chart aren't even worth considering nor will they have any explanation provided in the following section.

Same as support. Due to Senna's free damage on her passive and to a lesser degree the AD she gets from collecting souls (which is only a bit more than you'd get from actually having base ad growth) as well as Blade of the Ruined King's on-hit damage, Armor Penetration is extremely effective on her. Since Senna has a really really low base hp, she is an ideal user of LDR. LDR's passive gives her bonus damage against just about every single champion in the game and the full 25% against bruisers and tanks (where as most would only see the full amount against tanks). Naturally, build Mortal Reminder instead if the enemy team has significant sources of healing.

Same as support. BORK is hands down the strongest item on Senna. The stats and passive are both almost perfect. If you build this item, it'll be the most noticable power spike in the match. The synergy with Senna's A+Q+A combo and her ability to apply this damage safely at range are the reasons it's stands out so much. Since this item has seen nothing but buffs lately, there's no reason to believe it'll ever stop being the king of Senna's builds.

Same as support. This item is a good alternative to Lord Dominik's Regards when the enemy team has significant sources of healing. This includes champions like Soraka, Aatrox, Red Kayn and Irelia to name a few. I would recommend Lord Dominik's Regards over this item when dealing with self-healing tank champions like Dr. Mundo and Nasus since the bonus damage exceeds the value of the anti-heal. Dr. Mundo will full heal off ult whether you have Grievous Wounds on him or not.

This item is very nice for sustained damage output. It is a favourable pickup when the enemy team has magic damage threats and provides a lot of durability in both stat and kiting ability with the 20 move speed.

This item is very useful to compensate for Senna's rather weak wave clearing potential. Rush this first every time. It also has some additional benefits for Senna in particular. First, it triggers Presence of Mind when hitting enemies giving you free, safe mana. Second, you can Q enemies from far away and then trigger the passive on their minions. Excellent for pushing or holding wave against enemies when you can't step up. In lane, try to trigger Energized attacks on the enemy once you acquire Kircheis Shard for some strong harass.

With the buffs to Inifinity Edge and Senna now dealing 75% Crit Damage (just like everyone else), this item is quite compelling for both support and ADC. Currently, Senna has no good mythic. This is still the case. IE is strong but only marginally better than Youmuu's against squishies and marginally weaker than Eclipse against tanks. This is my current default mythic. I recommend this item unless the enemy team has multiple tanks - in which case, go Eclipse.

I decent all-around mythic. The extra mobility helps Senna survive but the stats are quite weak. You can situationally pick this based on enemy comp.

This is a very good mythic for sustained-output on Senna. Especially now that her Crit Damage is not nerfed, she deals very nice damage with this item. For support, sustained output isn't desireable since it forces your team to peal for two ADC's, as an ADC, relying on your team to peal is almost in the job description. This item is almost a free Lethal Tempo with solid stats and armor pen on the mythic passive. That's not even talking about the synergy with Senna's bonus crit from passive. Despite this, it doesn't provide any mobility and so you will often struggle balancing kiting and attacking with this item.

Building this item as ADC shifts focus from sustained damage output to burst damage output. One undeniable benefit is that the additional mobility can be essencial for kiting and repositioning which are key when playing an immobile champion like Senna.

This is a strong item that synergises well with Senna's kit. You'll definitely be looking to pick this item up either first instead of Statikk Shiv or after Blade of the Ruined King. BORK may not be a good first item since you'll want Noonquiver to help with wave clear and for it's impressive power spike.

This is a very helpful item when you are ADC Senna since you have much more mana issues than a support. Having said that, if you are able to be conservative with your mana and avoid buying this, you'll be able to avoid the weak build path and slow Tear of the Goddess stacking issues that Senna has.

A solid item pick for good damage, extra crit that you need as a farming Senna and the extra gold and execute which are very nice additions. Consider this instead of Blade of the Ruined King as your second item if you are ahead and want to keep scaling hard and fast. The bonus gold can also compensate for the gold reduction on subsequent kills against the same champions.

If you can avoid picking this as an ADC, do so. It should be up to a team mate to deal with armor shred. Having said that, if no one on your team can afford to build this item and armor shred is needed, go for it. You'll need armor shred against champions like Rammus and Malphite that build almost exclusively armor and also scale their damage off of it.

This isn't a particularly high damage item but if you need the armor, it's more reliable than Guardian Angel. Definitely look to getting Plated Steelcaps and only pick this item up if that's not enough.

If both Wit's End and Mercury's Treads aren't enough to deal with the magic damage problem (as will be the case for Veigar for example), you may need to get this. It shouldn't be a priority though since it is quite low in sustained damage output.

This item got gutted in 13.10's Marksman item rework and, as far as I know, no one is building it anymore. It's stats are bad, the shield was nerfed into irrelevance and the loss of a solid durability-oriented mythic passive tops it all off. Hopefully Riot realizes that this and (as they did for Galeforce make this item a mythic again. If they make it a mythic once more, this item could very well be a recommended for Senna both in ADC and Support builds since it had a surprising amount of synergy with her kit from it's stats alone.

Q+A Combo

Your bread and butter poke combo for lane, this will get you a stack of Absolution while also providing lots of healing from Piercing Darkness and Fleet Footwork if you're running it. You can also sustain this combo fairly well with Presence of Mind and your support item's mana regeneration.

Some match ups require care when executing this combo as champions like Alistar and Pantheon can engage on you when you get into your attack range.

Also there are Marksman like Draven, Caitlyn and Jhin that can poke you back hard. If your ADC doesn't help you with poke, it can quickly devolve into a frustrating 2-on-1 situation. Make sure you disengage and if needed, don't poke at all. Better to be behind on Absolution stacks than have the enemy lane put ahead on kills. If your ADC then complains that you're not being useful to them, mute them.

Finally, Ashe is a risky champion to poke against, especially in the above scenario where your ADC isn't going to help. She can permanently slow you and attack you until you're dead and if you're far enough away from the tower, she'll be able to do just that.

Full Combo

Senna's full damage combo is Q+A+W+A. It's pretty much just alternating abilities in between auto attacks to maximise your output. You want to use Last Embrace after Piercing Darkness to increase your chances of hitting it.

After completing this combo, just keep attacking while it's safe or disengage if it isn't.

This combo can be used both aggressively - to press for a kill, and defensively - to deliver lots fo damage while allowing yourself to completely disengage from the enemy.

If you have Black Cleaver you'll end this combo with 4 out of 6 stacks. after only about 2 seconds.

Always use E to get back into lane faster

A nice, simple one. E's cooldown is long but if you use it right out of base you get it back soon after reaching lane and the value of getting back into lane faster is significant.

If you recalled with your ADC, try to include them in your E so they get boosted too.

If someone leaves your E, they will keep the movement speed until it ends or they attack something so don't worry about getting ahead or falling behind of your ADC when doing this.

Safe Lane Sustain

If you're getting low on health in lane, fire your Q through minions to hit enemy champions. Doing so will give you the Q healing (obviously), trigger Fleet Footwork and give you a bit of mana sustain with Presence of Mind. With this, it won't take long before you're healthy enough to resume normal lane operations.

This tactic helps avoid recalling alone which is really bad in bot lane. You always prefer to recall with your ADC to avoid losing XP from them pushing the lane, them dying by over extending alone, them recalling after you get back to lane and you being alone, etc.

Don't even get me started about ADC's who think they need to recall every 2 minutes and the crash wave and repeat. If your ADC is doing that, just stay in lane and soak XP from a safe distance if you can. Maybe even take some last hits on Melee or Cannon minions.

Farming as a Support Senna

There's several deep dives on the pro's and con's of farming as a Senna support (most notably, taking cs that no one else will be able to get). The short and sweet of it is, an Absolution stack is worth about 50g worth of stats (0.75 AD, 1 Attack Range, 0.5 Crit Chance). This means that once you factor in the drop rates for souls, it is not worth taking ranged minions, barely worth taking melee minions and just barely worth getting early cannons. Later on cannons become more valueable as their gold increases.

This also means that if you go ADC and you're about to complete your 4th item (second last), it's probably worth not farming and instead doing your best to push waves without taking farm to maximise your scaling going forward.

There's also room for a duo to flip roles after the Senna ADC get's 3 full items and have the Senna pick up a support item and start exclusively scaling off of souls, takedown gold and passive gold.

Multitasking with Senna's CC

A big tool in my toolbox is the ability to focus one target in a fight and fire off my Last Embrace at a tank or other enemy to stop them from closing distance. Doing this in lane can net you a free kill if the support isn't already in position to back up their ADC and is also a useful skill when trying to secure picks or in spread-out team fights.

Use Ultimate when you're about to be CC'd

Senna's ultimate (similar to Lux) Dawning Shadow has an unstoppable cast. Only death cancels it and it doens't go on cooldown if that happens. This means that if you're about to get CC'd by someone you can effectively waste one second of their CC duration by triggering your ultimate cast time just before. This can be easily achieved against champions like Rammus, Seraphine and many others. It is especially effective against Renata Glasc's ultimate since you not only make use of that CC time, you also minimise the amount of damage you do to your team (which in Senna's case, is significant).

Obviously the above is subject to it being a good time to ult in the first place, don't just throw out your ult because Nocturne is about to get his E off on you but you're surrounded by allies and he's already going to die.

Exhause Usage

Senna works really well with Exhaust for several reasons. As a stat check tool, it gives her favourable outcomes to a lot more 1v1 fights. As a peal tool, it can be the difference between life and death. Finally, if you have a fight you're going to win but the enemy has flash or you're trying to greed for two kills in lane, you can exhaust an enemy and the chances of them getting away are significantly diminished.

It takes time to understand exactly when Exhaust is best utilized and if your allies ping it becasue you didn't use it and didn't want to, mute them. I have a zero tolerance policy for people telling me how to play when they are the ones that screwed up.

Healing Allies with Q

Some ADC's get it. Some don't. Your Q is instrumental to your safe, reliable and effective lane poking. Do not use it on allies outside of the following exceptions:

* You can't step up to poke or there's no one to poke
* Your ADC is below 30% and doesn't want to recall
* You can fire it through your ally to hit an enemy that's outside your range
* When taking epic monsters or hitting towers you can and should line yourself up with your ADC so your Q will hit them and the monster/tower.

In all other cases, use your Q exclusively to poke and set up engages. If your ADC complains, use the mute button.

Use Presence of Mind if you're out of mana

This one is kinda obvious but if you're running low on mana and it is safe to do so, just step up and auto enemies to get that bonus mana regen coming. You don't need to recall for mana unless you do!

More to follow...

As I remember more tricks I use in my games, I'll update this section to include them so watch this area! :)

The tier list template can be found here:
https://tiermaker.com/create/league-of-legends-pre-s13-items-15446387