Singed descended from a long line of Zaun's revered chemists. Even in his youth, his talent for concocting potions far outstripped that of his peers, and he quickly distinguished himself from his less extraordinary chemist compatriots. It came as no surprise to anyone when he was selected for apprenticeship by the infamous Warwick, master apothecary on a lucrative retainer with the Noxian military during their campaign against Ionia. Within Warwick's laboratories, Singed toiled without end, rapidly absorbing every detail of his predecessor's deadly craft. Singed had little concern for the death and destruction that was the fruit of his labors. By the time the curse of lycanthropy descended to claim his master, Singed was poised and eager to make the transition from workhorse to innovator; he was ready to share his genius by bringing a new brand of suffering to the Ionian front. His zeal for progress was unquenchable, and when suitable test subjects proved to be in short supply, the eager chemist was often thought to turn his volatile mixtures on his own flesh.

When the uneasy peace created by the League of Legends settled on the world, Singed journeyed to the one place where he was still able to showcase his beloved craft: the Institute of War. By this time he was barely even a man, his body both ruined and sustained by his ingenious craft. A thousand burns - accidents of shadow and flame - mar his ravaged form, and exposure to such harsh conditions has deadened his nerves, hardened his body, and strengthened his physique, transforming him into a veritable juggernaut. This, combined with a formidable arsenal of deadly concoctions, makes Singed a force to be reckoned with on the Fields of Justice.

''My deadliest dose shall bear my patron's name!'' - Singed, having just christened the Insanity Potion

This is the CORE ITEMS for my build

Early Game -

I always start with theese items because I like the extra mana from Sapphire Crystal and potions can always come to good use in early game. You can go with the Ruby Crystal instead of Sapphire Crystal if you want to but then you can't afford potions so I don't recommend it.

Then you should get Boots of Swiftness and after that complete your Rod of Ages

Mid Game -

Mid game you should go with theese items because then you will have magic resistance and armor so you are protected from both magic and melee attacks, and you will also get a good amount of hp regeneration from theese two items.

Late Game -

Or

I usually go with Aegis of the Legion and Thornmail but you can buy Zhonya's hourglass instead of the Thornmail, for some more damage with your poison and fling.

And

So this is where i have chosen Exhaust and Flash for my summoner spells and that is because i think that exhaust is a great spell for CC (Crowd Control) and not only can it help you get some poison in their face it helps the whole team when you can slow down your escaping enemies. Flash i have chosen because it's realy good to be able to just flash out of tower dives or spells such as Veigar's Event Horizon and Jarvan's Cataclysm .

Greater Mark of Insight:

I feel that the magic penetration from this rune is good for the poison damage, so that's why I recommend this mark.

Greater Seal of Clarity:

This one I like because it makes farming and getting creep kills with your poison easier when you don't run out of mana early game.

Greater Glyph of Shielding:

Magic resistance is always good early game you take less damage from magic harresment and it's abit easier to survive.

Greater Quintessence of Insight:

This quint you can change if you like, it works good for me though so that's why i recommend this quint.

Poison Trail:

This skill is the one you are gonna do the most damage with, I usually run around the enemy or infront of them it's almost best to be chased they will take alot of damage in the long run.

Mega Adhesive:

This is an AoE slow and has quite long range so it's great when chasing an enemy or you just need to escape.

Fling:

Fling is a spell you can have much fun with, How it works is that you target an enemy and it tosses them over you so you can just fling an enemy into your tower if they get to close or just fling them into the hands of your team.

Insanity Potion:

This is a great spell, you get extra AP, HP regen, 30% CC reduction and most of all insane movement speed that you can not only escape good with it's great for chasing ppl to just run infront of them with this spell active, fling or slow them and they will have a real hard time to escape.

That's all for now, I hope you find this build usefull.

Good luck!