Hello Summoners, this my first ever guide, so I hope I'll help you, I hope you'll enjoy it and I hope I'll get some support. Here I'll try to explain how I create an unbeatable mid-lane Diana.

If you leave comments (something I highly hope you will) please base'em on what I've wrote: ask a question, tell me if you tried it (and if you liked it), but please don't rush me about how terrible my guide is (which I'm afraid of :D)

So let's get started with Diana's champion spotlight Play Video

Pros + Extremely good farmer thanks to Crescent Strike and Pale Cascade + Good pusher in the begining of a game + Good ganking even under level 6 + Ranged ultimate Lunar Rush

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Cons - Too quickly loosing mana - Too often focused by the opposition - No crowd control - Hard escaping when Flash is on cooldown.

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Ignite will guarantee a kill if your target is escaping or you can't reach it due to CD.

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Flash will save your life when you are escaping from opponents that targeted you. It's almost obligatory to take Flash, because Diana has no abilities that might be useful for escaping.

• Greater Quintessence of Ability Power: Using that rune, you basically start the game with AP boost which is crucial for Diana.
• Greater Glyph of Ability Power: Using this rune you gain even more AP and harassing in early game is a lot easier.
• Greater Mark of Magic Resist:Using this rune will secure enough magic resistance in the beginning of the game.
• Greater Seal of Armor: And if your enemy is an AD champion (which is less likely but still likely) using this rune will guarantee you an acceptable armor stat in the early game, so your enemy will experience some problems with draining first blood from you.

• Start with Boots and 3 Health Potion so you won't need to recall.
• Than a Doran's Ring to get some HP and AP.
• Make a Mercury's Treads or Ninja Tabi. It depends on your opponent's base - if it's AP make Treads, if it's AD than Tabi. Another possibility is buying Sorcerer's Shoes for magic penetration.
• Now buy a Giant's Belt to gain more health. If your opponent doesn't take your HP leave that item for now and buy it after you buy the other items required for Rilay's Crystal Scepter.
  And now let's focus on AP
• Get Amplifying Tome and Blasting Wand and once this is done upgrade to Rylai's Crystal Scepter
• Rabadon's Deathcap is a quick way to gain much AP with only 1 item.
• Lich Bane will allow you to deal tones of damage with basic attacks.
• Finally, if you have gold, buy Zhonya's Hourglass to guarantee armor, extra AP and a useful UNIQUE active.

• 

  Passive

  Moonsilver Blade will help you farm in the begining.

• 
  Q ability

  First master Crescent Strike as your main source of damage.

• 
  W ability

  At level 4 spend the point in Pale Cascade to accelerate the farming and to ensure some defense if needed. It's also useful when you pull back someone with Moonfall.

• 
  E ability

  At level 2 spend a point in Moonfall so you will be able to pull back and slow the escaping target. Master that ability as your second.

• 
  R ability

  At levels 6,11,16 spend the points for your ultimate, Lunar Rush.
  

  One advice

  - use it right after your Crescent Strike 'cuz that allows you to strike twice with your ulti ability.

  Ability Sequence
  1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18

Enough theory. Let's practice some kills.

In early game

focus on farming and harass your opponent. Try to do this at once, because Crescent Strike damages everything on it's way.Try to push your enemy. Once your opponent recalls attack it's turret but DO NOT destroy it yet (it's still the beginning of the game and you need to farm). When the turret is extremely low gank if your enemy isn't around, or if it is try to pick a kill.

When you get to level 6

Show your opponent that you really want to slain him. Harass him/her and play offensively (but do not take high risks). Your attack should look like that:
1. Attack with Crescent Strike
2. Lunar Rush (remember to use it twice!)
3. Basic attack (click on the right mouse button)
4. When your opponent tries to escape (trust he will try thanks to the damage you have inflicted) pull him/her back with Moonfall and immediately use Pale Cascade. Now your Crescent Strike CD is up, so use that ability again. Ignite if she/he's still alive (which I highly doubt).

In mid game

go for ganking, but don't forget to push on your lane. Instead of farming harass your opponents lowering their HP. Farming is not obligatory, but still a good way to improve your champion.

In late game

make sure you take part in ALL the melees to secure tones of damage inflicted by your team.

NOTE: If you spend your mana too quickly, feel free to give yorself a chance with The Ancient Golemif there is no jungler in the team.
Try

NOT

to start

Melees,

aim for joining them. It's about timing.

I love that champion. It's really funny to play with Diana and to watch how your opponent HP is getting low. If you guys have any questions or comments about my guide, please, feel free to ask. If you like it, please give it a high rating :)
Finally I want to thank JhoiJhoi for making such a great Karthus guide. Thanks dear, I wouldn't be able to make my guide without your help :P

"A new moon is rising"!