Vi Support. Yep. There are other supports who do stuff better than she does. However, Vi works as a jack-of-all-trades, as well as being a potent kill threat on her own. And unless there is a major ADC skill gap, bot lane will never be as much of a stomp fest as top lane, so there's nothing you can't do in lane that any other support can.

But most importantly of all, Vi Support is fun. You can play the entire map. You go wherever you please (move over Dr. Mundo). You make game-changing plays while on a support budget.

If you play her top, mid, or jungle, you already know how it works, so bring her down to bot lane and kick some butt. If you want to play support but find the likes of Blitzcrank and Lulu and Leona boring, Vi might just be the thing.

Let's explain the build a little. Please use your common sense to make adjustments (e.g. take one or two MR runes against Karma, rush Executioner's Calling against Soraka, and so on).

Summoner Spells

Flash/Ignite are the standard support spells. Ignite has a short CD, so don't worry about using it often. Sometimes you want Exhaust. Be sure to study the enemy team comp if you plan on taking it.

Runes

Most of the time Fleet Footwork is our best friend. Vi lacks the sustain of someone like Alistar, so this rune will compensate. The healing is useful throughout the game. Sometimes the movement speed can surprise the enemy too. On the other hand, Aftershock is an early game rune for playing aggressively. Later this gives you the option of not building Iceborn Gauntlet (but be careful).

Vi needs Presence of Mind to maintain her, ahem, presence in lane. Conditioning is a good scaling rune, but the other options can be more comfortable early game. And of course Vi likes all sorts of Tenacity.

Items

Most of the time Iceborn Gauntlet is the best mythic. It offers everything Vi wants: tankiness, CDR, damage, and even more CC. The CDR means you won't need to rush Axiom Arc. The other core items provide more survivability and CDR.

Really, Vi can build pretty much anything within reason. The other options are there to maximize either CDR or tankiness. Axiom Arc is a great snowballing item when you have one or two allies who can reliably get kills. Essence Reaver gives her additional mana and burst damage.

Ability order

Take R Cease and Desist whenever available. Max Q Vault Breaker first to lower the CD. You can get it down to 4-5 seconds by mid-game. Usually, prioritizing E Relentless Force is better than W Denting Blows because you can't reliably proc W more than once (you are not meant to be the carry). Experiment with leveling E and W in different ways depending on how much mana you're comfortable with using.

Vi Support has only two phases: before level 6 and after level 6.

Before level 6

The usual support duty: focus on getting Steel Shoulderguards completed. Hide in bushes. Get Oracle Lens on your first or second back and destroy enemy wards. Move around a lot to stack Fleet Footwork. Ward the enemy jungle if you have the chance. You can invade their jungle if your jungler is also there.

Despite her usual playstyle in other roles, Vi is not good at committing to an all-in as support! Her Q knocks the enemy back and is on a fairly long CD before mid-game. You should only go for an all-in if your ADC can follow up.

On the other hand, Vi excels at frequent trades to wear down the enemy. All trades start with Q. Make sure to hit Q so that it procs Blast Shield. Run away if the enemy is able to disengage (for example, Caitlyn's 90 Caliber Net). Otherwise follow up with AA-(E)-AA to proc W, reducing the CD of Blast Shield. As long as the shield absorbs some of their poke, this is a favorable trade.

After level 6

Here is where things get fun, where your game knowledge is really put to the test.

Most of your playstyle revolves around your R Cease and Desist. Since you are able to dash through walls with Q, use it to get vision around the map. Look for opportunities to turn 1v1s into 2v1s. You're almost guaranteed to get a kill or burn a Flash. You can chain CC the enemy with Q-R-Q with very little time in between.

In large teamfights, you want to survive for as long as possible. Find their main damage threat and lock them down. Try to reduce the CD of Blast Shield by hitting the same enemy 3 times. Your shield can absorb a lot of damage over the course of a teamfight, similar to Riven.

A good thing about Vi is that if bot lane is behind but mid or top are at least even, you can always make a play somewhere on the map with R. But... if everyone is behind, then you're outta luck, what can ya do? Just smile because you're playing Vi. Inting has never been more satisfying.

That's all for now. Have fun!