The Mad Alchemist has gone through multiple permutations in his career, most recently gaining a buff/nerf to his Insanity Potion that stops his one-man tower backdoorer career, but brings up even more the fact that Singed, as a character design, is fundamentally designed to simply annoy the living **** out of people.
Too tanky to be considered a DPS, too fast to be considered a tank, and too damaging to be considered only a utilitarian character, Singed is best described as a character with one single goal in mind, and the ability to make that goal happen. That one goal is simple: Cause as much chaos in the enemy lines as possible, and make them FEAR YOU.
Basic Item Build:
I start with Boots. Always. There is absolutely no reason you shouldn't start with boots. Ever. Ever ever ever. Load up on full health potions, during your first few levels and your first few forays into annoying the **** out of your opposing lane members, you'll need them.
When you come back, you want to get Boots of Swiftness, and progress into either a Sunfire Cape, or a Banshee's Veil, depending on what kind of team you are facing, heavy AD or AP. Either ways around, either of those items are core unless you are facing a pure AD or AP team.
The next time you come back, start building towards the second of the two items, either Veil or Sunfire.
Next thing you want to get is Rylai's. I cannot stress how important this item is for avoiding ganks and overall being ridiculously obnoxious to your enemy. After all, your poison trails activate Rylai's, and nothing is better than a slowing DoT that cannot be avoided by the enemy if they want to advance.
From this point on, you want to generally build towards whoever is causing the most damage at the moment. If it is an AP caster, I suggest building Force of Nature. Not only does it give you Magic resist, it gives you a massive regen bonus that ensures you are absolutely unkillable, and makes you even faster than before, necessary to ensure that no one in any lifetime will be able to catch you.
From there, Randuin's Omen is never a bad choice. I haven't considered Frozen Heart yet, but I can't see it being a bad thing, considering how it slows enemy attacks down. You shouldn't bother with Warmog's, as you will have more than enough health to survive any circumstance thanks to the fact that you also convert mana into health with your passive, and Health stacking only encourages the enemy to get a Bloodrazor and make your day overall not very positive.
x9 Greater Mark of Insight (Oh, look, your MR doesn't stop my Poison!)
x9 Greater Seal of Resilience (For his nerfed starting armor.)
x9 Greater Glyph of Undecided (I haven't decided what I want here. I never have problems with mana, so Replenishment is right out.)
x3 Greater Quintessence of Swiftness (I WANNA GO FAST.)
For Offense, take Archmage's Savvy (Boost to ability power, however so slight.) x3 and Deadliness (Hate Exhaust on Singed, not worth it.) x1, Sorcery (To get to Archaic Knowledge.) x4, and Archaic Knowledge (OH LOOK, YOUR MR DOES EVEN LESS.) x1.
For Defense, take Hardiness and Resistance x3 each. This will aid in your survivability.
For Utility, take Perseverence (Helps with any mana regen issues) x3 and Ghost (Makes you faster. Duh.). Expanded Mind (Increases Mana, which increases Health and lets you spam more poison. No duh choice.) x4, Awareness (To get to Quickness) x1 Meditation (Mana regen again, and to get to the highlight mastery.) x3. Quickness (FASTER FASTER FASTER) x3.
You should take Ghost (Did I mention that going fast is a good thing already? Because GOING FAST IS A GOOD THING.), and Ignite (Awesome for landing that last bit of damage on someone that just went behind a tower).
Generally speaking, you should be staying near the tower as Singed until your minions come about. You could very well go for Fling early game and try for the early first blood, especially if your lanemate is one of those with a nasty stun early game, but generally speaking, Singed isn't built for that, and you shouldn't really bother with it. Leave that to the assassins.
What you SHOULD be focusing on, however, is poison misting the enemy lines as much as humanly possible. Remember to focus on short, quick puffs of the delicious purple mist, and even make a screen to prevent melee people from scoring last hits on your own minions without taking some damage. When there is an opening to fling your enemy behind your own lines, take it. Even if its a setup, you should be resilient enough to get out of dodge if things turn sour, not to mention Ghost and the ever-present poison mist following you preventing chase.
With your 3 health potions and playing strategically and defensively, you should be able to gain quite a bit of gold, along with maybe even an assist or kill or two. When you get the chance, head back and get your Boots of Swiftness. The first stage of the fun has begun, and those boots are your ticket to gold.
When you hit level 6, something magical happens. I call it Singed's Puberty. That's when Singed stops being only a slight annoyance, and metamorphoses into a full-fledged ragequit butterfly. When you hit level 6, you gain Insanity Potion. This little gift from Riot essentially makes Singed 2 levels above where he is right now, gives him massive speed boosts (I've gotten up to 800 Speed), massive health and mana regen (Especially when stacked with FoN), and makes pretty much everyone seeing him RUN AWAY. This is the point where you should start really dealing some serious damage and really unleashing the fury on your enemies. You should be able to handle your lane relatively uncontested, and when ganks do try and come, you should be able to slow them and zip away without any issue whatsoever, or just plain weather out their assaults and poison them to death.
Along with this, and this may be controversial, you should start ganking.
Now, some self-respecting people might say, "Singed? GANKING?! What the hell are you ON, my good sir?!" But let me deliver my case plainly, and without complaint.
Singed can slow enemies down for a honking large amount, and fling them behind him. They're then poisoned, and Singed can wail on them. They get behind a tower with low health? Pop Insanity Potion, with its insanely low cooldown, and tower dive that sucker without any real issues. Along with that, a random Singed popping out of nowhere and instantly delivering death and horrible things on your opponent strikes fear into the hearts of your opponents. They start not wanting to face Singed, and that carries over into late-game teamfights, and you causing chaos in them.
By the time you reach level 10, you should have gotten your first real defensive item, be it Sunfire Cape, or Banshee's Veil. Now the fun REALLY starts.
Congratulations, from this point on, you should be nigh unkillable.
With a massive focus on Tankiness, and your insane move speed, you should be able to simply dive into teamfights, laughing as they all try to focus and burst you down, and unleash hell and havoc upon their team. When the teamfight goes south, you can just lay down a puddle of slow goop and trail your magical purple fun juice all over them, preventing them from chasing your likely weakened, if not dead, teammates.
Your focus in teamfights should not be the defensive, passive role of a regular tank, instead diving straight into the fray and unleashing pure and utter chaos as they try to repulse you and stop you from poisoning, slowing them, and throwing them all over the place. That's what Singed is about, after all. You are not a true tank, and you have nothing that will force enemies to attack you. But what you do have is some great CC abilities that sew discord, chaos, and overall bad things amongst your foes, and you have the raw durability to prevent enemies from simply focusing you and making you die before you can unleash these talents. You should finish up your build VERY quickly by this point, either getting tons of kills or tons of assists, and pretty much act as the battering ram that brings your team to victory. Congratulations, you just won a game as Singed, and the opponents will now be going off to the Champion Feedback Forum to scream, "OMG SINGED OP QQ".
Work in progress.
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