Scylla, Monster of Mid Lane (S4)

Scylla is probably the most extreme glass cannon in the game as of now, making her a great choice for anyone who likes to kill entire enemy teams while they still had 75% hp remaining. By that, I mean everyone.

Pros:
Best(?) Glass Cannon
Can get many kills in quick succession
Relatively long range & ability aoe
High mobility
Moderate utility
Lots of power spikes
No part of the game is especially weak

Now, the biggest pro & con is: Scylla is a snowball god. If you get 1-2 kills mid by min 5 without dying, it's gonna be a great game for you. If you die 1-2 times mid without getting kills by min 5, it's gonna be a very rough game. You don't need to snowball that much, but it is important that you get the ball rolling early.

Cons:
Very squishy
Abilities are slow and telegraphed, making them easy to dodge
Countered by high mobility and burst enemy gods & items
NEEDS to stay in back of fights at all times, no matter how high your health is, if you try and tank for even a second as Scylla you're gonna die

Note that the Glass Cannon Mid build is the one I use, and the one this guide will be focusing on. I may eventually add sections referring to the other ones.

Passive: fairly straightforward, but take note every time you max an ability as you have just hit a power spike, and it will wear off in 1-2 minutes

Sic' Em: I recommend using this further into fights as opposed to setting up with this. It's much better to use this to chase than Sentinel (3), but alternatively you can use it in 1v1 situations to proc Polynomicon.

Crush: EXPLOSIONS! SUPER high damage nuke with long range and large aoe. This is your bread and butter for any occasion - clear, damage, teamfights... make sure your soul stone has 5 charges before you use this, if possible. The magic protection debuff isn't so useful in 1v1 situations as the enemy will know and it's coming and will just sidestep out, but in teamfights when the enemy is distracted the amp can be super useful for not only yourself, but other mages / guardians on your team - especially if you have a big teamfight pull / cc god such as Ares or Hades. If you find much of the enemy team stunned are especially distracted and all clumped up, I recommend using Crush and then following up with your ultimate. You may just get a penta.

Sentinel: this is your mobility skill, using this to engage is risky as you're extremely fragile, and your mobility is your only saving grace. I recommend using this to escape or reposition during fights, but it can be useful in 1v1 situations to chase if the enemy also has an escape. In addition, at max rank this skill gives a huge amount of vision, and could be nice if you're protected by tower or lots of teammates and are worried about the enemy engaging from the side.

Now, for your coup de grace - I'm A Monster

Your ultimate is by far your most complex ability, but studying it carefully can make it the best ultimate in the game. This should be the finishing move of your combo, try not to use this before your other abilities and poly procs (except Sentinel). Also useful for sniping / getting enemies separated by a wall.

In 1v1 situations: aim for the center of your enemies, moving *slightly* toward the direction they're moving in. If they're good they're going to try to dodge with pretty good reaction time, so don't overdo this. If the enemy is particularly fast you can aim a bit further towards their destination, but don't overdo. I account for about .25 seconds reaction time. Striking as quickly as possible after changing into your final form can make it harder to predict and therefore harder to dodge, but a good enemy may be able to evade you no matter what you do (unless they're distracted).

In teamfights: this is where this ability really shines. Enemies are distracted, so you should be able to take as much time as you need to aim and hit as many of them as possible. Provided you hit at least 2 enemies and killed 1 of them, you're on your way to a penta with each follow up. Assuming you're fully built, few gods can withstand more than one of these at a time.

Here are rough health thresholds for a OHK by your ult:

Early Game (Pre 10 Min):
Hunters/Mages/Assassins: 1/3 hp, 33% hp
Warriors/Guardians: 1/4 hp, 25% hp

Mid Game (Pre 20 Min):
Hunters/Mages/Assassins: 1/2 hp, 50% hp
Warriors: 1/3 hp, 33% hp
Guardians: 1/4 hp, 25% hp

Late Game (Post 20 Min):
Mages: 2/3 hp, 67% hp
Hunters/Assassins: 1/2 hp, 50% hp
Warriors: 1/3 hp, 33% hp
Guardians: 1/4 hp, 25% hp

Again, these estimates are rough, and I have no way of possibly knowing all the variables in every game. I'm assuming Mages & Hunters are building no magical defense items, Assassins are building hybrid with focus on offense, Warriors are building hybrid with focus on defense, and Guardians are building full defense. In addition, I have assumed that Mages will not have any hp items until late game, in which they may have 1, Hunters will have 1-2 hp items by late game, Assassins will have 1-2 hp items by late game, Warriors will have 2-3 hp items by late game, and Guardians will have 3-4 hp items by late game. If this approximate magical protection to hp ratio isn't the case then you can assume they will be slightly worse off, and therefore you'll be able to OHK them with higher % hp.

These values were determined off a Scylla that's ~2-0-0, with fairly decent farm. If you're snowballing well then you can add about 2% hp to the threshold for every kill you have (i.e. if you're 5-0 then you could kill a mid game hunter with ~60% hp). If you're behind then I can't really calculate how far behind exactly you are, but just subtract 5-10% hp from every enemy you hit - better safe than sorry when every kill counts.

Starting Items:
Simple and effective mid starting gear, make sure your soul stone is at 5 before Crushing. Chalice of Healing is good sustain until you have your Polynomicon, but isn't needed if you're up against a super passive mid or jungle.

Shoes of the Magi:
While Shoes of Focus may seem good (especially since we're going Book of Thoth), your goal is to do as much damage as possible, and cdr boots are simply outclassed by pen boots. I did the math and you'll be losing ~50 damage per ability early game, ~75 damage per ability mid game, and ~100 damage per ability late game. Consider your two most frequently used abilities - Sic' Em and Crush. They both have 10 second cooldowns,so would you rather have -1 second cooldown, or +100 damage?

Book of Thoth:
Great for raw damage, not too much to be said here. Only 3% of your mana will be converted to power, and while that will help a ton when you have 1000 mana by min 15 (30 extra power), you don't need to sacrifice build efficiency just to buy all the mana items you can. Soul Reaver gives a ton of manaa, but there are simply better items since you do a ton of damage without a long cd non-scaling damage source.

Polynomicon:
This is really a playstyle item. I love it, as Scylla's power is so ridiculously high that you're basically getting another ability's worth of damage, and your cooldowns complement poly's proc timer, but if you'd rather keep your distance and use your fairly long range abilities then that's fine too. Go for Bancroft's Talon instead, it's super strong on Scylla as you're likely to lose some hp if you're within a mile of the nearest fight.

Spear of Desolation:
Great pen item with nice power and cdr, I did the math and this outclasses Obsidian Shard by ~80 damage on non-tanks by the time you're getting it. Obsidian Shard is cheaper and melts tanks faster, but you shouldn't be focusing tanks anyway, and I'd much rather have the bonus effects of Spear for the extra 450 gold.

Chronos' Pendant:
By this phase in the game you need more cdr in order to stay relevant in fights, and Chronos' Pendant is the best item in the game for just that. An alternative for more damage is Shaman's Ring (your Crush magic protection debuff will proc the 10% damage bonsu), but I feel the effective 30% cdr is more needed by this stage. Fights will start getting longer, and if you can get out two Crushes in one fight you're going to be doing a lot more damage.

Rod of Tahuti:
Super strong mage item, once you've completed this item you get REALLY powerful again. You can probably add about 15% to your OHK thresholds for a bit - it's that good.

Heartward Amulet: this one is actually only here to let you know I already factored it in for the OHK thresholds. Don't worry if you see a Heartward, it's bound to happen almost every game... but if the enemy doesn't think you're a threat, you can definitely use it to your advantage.

Anti-Heal Items (Pestilence, Brawler's, etc.): not a big deal, you shouldn't be taking much damage anyway, the only situation you need to watch out for this in is 1v1s. You can afford to lengthen the time of your combo with poly procs since you're getting all that lifesteal, but if the enemy has strong anti-heal you may just want to kill the enemy as quickly as possible (using all your abilities at once), as you can die in less than 5 seconds in a 1v1 without that lifesteal.

Stone of Fal: this is the big one, this REALLY messes up your ult. Anyone with this item automatically lowers their OHK threshold to 1/3 hp, or 33% hp, and there's nothing you can do about it. Sorry mate.

Ancile: this one hurts a lot, but admittedly not as much as Stone of Fal. Your ult won't take a hit, as you're cc immune during it, but be ready to compensate for that silence by running or using beads before it's too late.

Runic Shield: your magical power is above 700 by late game, that 50 power reduction is gonna hurt but it won't be devastating. Just decrease the OHK thresholds by ~10%.

Magi's Blessing: not too complex, just make sure you aren't banking on your root in 1v1's if the enemy has this.

Crit items in general: do NOT try to 1v1 people with these. You will instantly melt.

Since Scylla is very xp dependent and has good clear, I recommend this start - clear first wave, do mid xp camp, clear second wave, do other mid xp camp if it's still up OR go to next inter-wave activity, clear third wave, take speed and fire camp then separate with your jungle since you can clear, escape, and need dat xp

Level 2 - get Sic' Em if you're expecting to get a kill with your jungler soon, otherwise take Sentinel as it will be useful in more scenarios and provides some nice MP5.

Level 4 - if you went Sentinel level 2 and aren't expecting kills any time soon, you can opt to skip a level to get both level 3 Crush and a level in your ultimate once you hit 5. You'll have stronger clear, and your ult is way better for securing kills than Sic' Em.

Level 8 - skip this level to max Crush and get another point in your ult at 9, unless you very recently used your ult and think you can get to level 10 by the time your ult is off cd

Level 13 - it's practically always a better idea to forgo leveling your ult in favor of maxing Sic' Em, unless there's going to be a major fight very soon and you already know about it. In that case, your ult will gain 76 more damage per hit than if you were to level Sic' Em.

I'm currently a Mastery V Scylla, hoping to get to Mastery X within the month. At the time of writing this I have 2400 hours in Dota 2, 300 hours in Smite, and I'm not new at all to theorycrafting. Whenever I have free time and I'm not at home I like to think about the best ways to min-max the gods / heroes I play. It makes the game way more interesting in my opinion, if you haven't already you should try it.

This isn't my first build / guide by a longshot, but it is my first SmiteFire guide, and I'm always open to criticism if you can prove your point. Leave me as much feedback as you like. Also, I see a lot of fancy formatting on other guides, I may implement some of that later, but it really isn't necessary and I don't know how. Fairly sure I can get the same point across without the effort.