Early Game
Finish this first for mana. Do not finish this if you're going Tranquil Boots.
Do not build this if you're going Tranquil Boots. Finish this second to upgrade to Aquila.
Magic Wand will save your life and net you kills.
This is the best item in the game. You should have one on you from ~3-5 minutes until you're 6 slotted late game. If you forgo this early game it's because you're going Midas.
Core Items
Sell this to finish more expensive items, or to carry TP when you finish the other 5 items here. Yes, it's better to keep the Magic Wand than Aquila mid/late game.
Use Strength mode until Luna has approximately 1200 health in Agility mode. This amount of HP seems to be the point when you can safely survive fights without the addtional health.
A must buy if the opponent has a lot of magic or lots of stun/disables using magic.
Use a dominated creep to stack ancients at x:53
Take Alpha Wolf to teamfights/pushes for 30% more damage teamwide.
Manta peaks in the midgame and pushing.
Late Game
THE "AGILITY CARRY" ITEM.
Knowing when to activate this is very important. Too early, it is wasted, too late you're already dead.
Trade your Treads/Tranquils for Boots of Travel once you're 5 slotted. Do not wait until you're 6 slotted with Treads because TP becomes more important as the game goes on.
A must buy against Phantom Assassin and Brewmaster or any Butterfly/Halberd carry. This item is the only bash item; for ranged carries.
Situational Items
Fun item on Luna and useful depending on the build. But not a Core Item. Especially useful if you're behind for escapes.
Buy it if you are against Faceless Void, Anti-Mage, Phantom Assassin, Phantom Lancer or Spectre. Luna cannot outcarry them without incredible damage late game (50+ minutes).
Butterfly, Manta and Satanic aren't enough once these carries have their items (which they will eventually).
Rare buy, 6th item for pushing power and attack speed.
Rare 6th item. When you need more damage, it's this, Skadi, Mjollnir, MKB or Divine. That's it.
Now that Diffusal is not UAM, you can grab this on Luna if you're having trouble finishing Manta Style with Ultimate Orb. In fact, I've been building it after BKB or Helm of Dominator in most my pubs with great success.
Rare 6th item. This is usually more useful if you need additional survivability with reduction of dps on the enemy team. A surprising good buy when against agility carries.
You should buy this if you know their Carry is going Midas. The usual suspects include Druid, Doom, and Nature's. Occasionally Void, AM, Bambi, etc...
Dota 6.83 Update. In order to keep your ultimate relevant late game, you have to get Scepter. Maximum hits per hero is capped off at 4. If you are 1 on 1, mid/late you will not win without this item. I wish they kept the maximum hit limit without Scepter, but Dota changes... and this is the change.
Buy these for more speed. Do not pair with Healing boots, those are no longer viable for Luna in 6.83
Right Click Counters
Buy this for JUGGERNAUT'S OMNISLASH. Works versus Viper, Drow, Clinkz, Void, PA, Anti-Mage, Phantom Lancer, Chaos Knight...
Build up to this when you need a Ghost Scepter against dps heroes so you can make them pay using your magic.
Buy this if you can't finish Ethereal Blade. You should already have Ghost Scepter. Ideally your supports should buy this for the team.
Other Items
Bought when HP is more important than the additional lifesteal Satanic would give.
If you're not Helm of the Dominator, then you probably want this. Luna is surprisingly effective with the attack speed buff despite her low health pool. Usually used with Shadow Blade for escaping.
Do not buy these, these are not viable in 6.83
