Hi, this is my first build on Mobafire, so do not expect me going in to details on everything, i will explain my masteries, runes, item build and spell sequence


I am not from england so please excuse my grammar.

I take Greater Mark of Magic Penetration x9 becouse of harder harass early game. And with syndra this is pretty strong since her dark sphear is such a short Cd.

I take Greater seal of Clearity x9 becouse i can get mana quicker, with leads to stronger laning phase, simple as that

I take Greater Quintessence of Ability Power and Greater Glyph of Ability Power becouse of early harass. And in lvl 6 this means u can 1 shot their ad in one single combo.

I take the original 21/0/9.
You might wonder why i take 2 points in Butcher , this is for easier last hits.

I do not think this needs more explanation.

1. Boots I take this to dodge skillshots, u can roam faster to lanes who are struggeling, and if your mid enemy is stupid enough to buy Doran's Ring you can smash his/her face since the yaint got no Health Potion witch means u can survive longer in lane.
2. catalyst the protector Mana, manaregen, HP, does this need more ezplanation?
3. Rod of Ages Manaregen, Health, and mana, this is the perfect earlygame item since Syndra is very mana hungry.
4. Sorcerer's Shoes From this your abilities does alot more dmg, and you move faster, if you feel like it's too long to wait before getting it yo can get it after Catalyst the protector
5. Deathfire Grasp Exstremly good item, you can basically chug 40% of your enemys hp with this, easy kill for syndra. Use this, then W-R-Q, BOOM DEAD!
6. Rabadon's Deathcap Alot of AP(ability power) + i scales with how much ap you have, AKA you get 30% more AP! A must have for all AP Carrys
7. Zhonya's Hourglass Trust me you will get focused in teamfights, this is a good strong item, and yiu enemys is gonna get comfused when you pop your zhonyas, witch means you teammates can pick out the enemys ad carry since the enemy will probably wait for your zhonyas to end. a good item overall.
8. I choose Banshee's Veil becouse of survivability, as i said u get focues alot, and it is nice to have a shield that blocks the first incoming ability + mana and HP! If the other team have alot of AP champs u can also consider Abyssal Mask
   

This is how your combo should go, i have tested this out and it seems to crush every opponent: W-Q, this is early game. very strong harass.
When you get your ulti this should be your combo:
W-Q-R-Q if it is not dead yet scatter your sphears and kill with ur E and you Ignite

Ignite to finish of the remaning hp og enemys, also counters

Is a great Escape tool incase u get ganked. It can also be used for chasing and hitting that last dark sphear

That my guide, it's a little thin, but i might fill in some stuff if you guys find it usefull, leave some comments about good and bad things, i would appreciate it :)