Crystallis - A Build for Crystal Maiden

You should add more items and Black King Bar as core.

Nice guide, I've been playing a lot of CM support lately and I value outside perspectives on the matter.

I've personally been going down one of three build trees depending on the lanes and how hard I have to support.

Skill-wise it is usually Frostbite>Aura>Frostbite>Aura>etc for me at the start unless for some reason I'm forced to go mid support.
In which case I pick Nova over Frost.

I tend to not pick up regen items and compensate for it with positioning to keep myself "off the map" while close enough to gain levels and be ready to gank assist/defend the carry.
Dropping Frostbite on medium creeps for gold.
I only stack easy camp and creep pull when the lane partner is comfortable with it.

Item-wise I either:
1.Hard carry Courier and Wards at start, grabbing 2x Gauntlets of Strength to build into Urn of Shadows.
2.Pick up either Courier or Wards with the 2x Gauntlets of Strength and a Ring of Protection.
3.If the situation calls for it I might pick up RoB at the start and some tangos.
RoB start is mostly only if you random-ed or rest of team already covered the support stuff and you want to go aggressive early with your ganker/carry buddy.
It gives your lane some mana until your get your aura up, then it builds into your Tranquils and Urn.
Obviously you wouldn't build Urn if someone else was, and only if you expect successful kills early.
I tend to favor Urn over Mech early as I frequently am tight on mana from constant use of Frostbite for jungling/ganking.

Nice Guide, +1

There are a few things I don't agree with though:-

You only need 1 level in Arcane Aura early on, maybe a 2nd is worth it if you have a highly Mana dependent Hero like Storm Spirit, Timbersaw, etc. who can blow through their entire Mana Pool in no time in order to get Kills and Snowball, but that's about it. Maxing Crystal Nova 1st gives you extra Damage which should be your main source of Harrass and Nuking early on. After that, Max Frostbite since you can still get by from 1 point in Arcane Aura.

Leaving Freezing Field until lvl11/14 is a sensible choice since you don't have enough Mana until later on to use it though

Just be careful not to Pull too often and leave your Carry trying to Farm under the Tower, you may also need to go into the Lane to Harrass as well, especially in a 2 vs 2 Lane and then there's Warding and Ganking...

You'll also Push the Lane out this way, which is fine if you're ready to take down the Tower, or are trying to Counter-Push, but you should try to avoid the Creeps, and just hit the Heroes on the other side most of the time.

I'd also add Force Staff to Situational Items, it's practically Core since Maiden is easy to catch out. Same with Ghost Scepter, Black King Bar, Necronomicon and Scythe of Vyse. Maybe even Urn of Shadows and Hand of Midas if you build them fast enough. <}3