Need some help with Support item building.

- Ghost Scepter : it makes you immune to physical damage and it will save your life a lot. Get it if you want to avoid feeding. It counters right-clickers like Ursa or Clinkz. If you get ganked you can just ghost and TP out.

Welcome to Dota!

Playing support is a bit of an art because you build completely different items every game. Indeed as you say the question is not "what does your hero need" but "what does your team need". The point of supports is that they're almost completely item-independent and hard supports can be played without a single item!

The stereotypical hard support build is Arcane Boots -> Mekansm -> Force Staff. You can't go wrong with that build so if you want a quick answer you can just make that.

But in general it's more of "what does your team need at a specific moment" :

- Mekansm : your team needs one in almost every game, it's the best item for early/midgame teamfights and early pushing. You make mek because you want to push early, as soon as you get your mek call your team, group up, and push some towers.

- Urn of Shadows : it's basically the poor man's Mek, it's also a pushing item because it heals your teammates during pushes. It's a great item on ganking supports like Enchantress, Vengeful Spirit, Crystal Maiden... Can replace Mek on mana-starved heroes.

- Drum of Endurance : some people like drum on supports but it almost always fails the "would I rather have a mek" or "would I rather have a forcestaff" test. Extremely situational, drum is mainly a mid-game item for carries.

- Force Staff : it's a great item on any support and you can't ever go wrong by making a forcestaff. It's an absolute must if the enemy team has slowing heroes like Viper or Drow Ranger to save yourself and your teammates. It's great for escaping, saving teammates, chasing, and generally making some plays happen.

- Ghost Scepter : it makes you immune to physical damage and it will save your life a lot. Get it if you want to avoid feeding. It counters right-clickers like Ursa or Clinkz. If you get ganked you can just ghost and TP out.

- Blink Dagger : It's an absolute must if your support is also an initiator. If you're playing Enigma, Sand King, Earthshaker, Tidehunter, Treant Protector etc then you really need that blink ASAP and it's often the first item you should get - Mek first is the only viable alternative.

- Pipe of Insight : it block magic damage for your team. Get it if they have a lot of AOE nukes like Zeus, Invoker, Sand King, etc.

- Eul's Scepter of Divinity : it's both an item to save yourself from getting focused AND a disable that removes an enemy hero from the fight completely for 2.6 seconds. It's good for ganking especially if you already have Blink dagger/Forcestaff, and removing that pesky Axe or Wraith King from a teamfight is always a good thing.

- Vladmir's Offering : Yes, Vlads is a SUPPORT item, people build it on carries way too much. The aura gives armor and damage to your team in teamfights, and lifesteal to your melee carries. It's a great item to buy if your team has a lot of melee right-clickers e.g Phantom Assassin, Anti-Mage, Tiny, Sven, Slardar, etc OR if the enemy team has a lot of armor reduction.

- Veil of Discord : Amplifies your team's magical damage. Get it on supports with heavy AOE nukes like Venomancer, Lich, Sand King, Jakiro OR if the rest of your team has a lot of magical damage like Invoker.

- Necronomicon : this is the game's pushing item. Get it if your team wants to push. Generally you want to push if the enemy team has farming hard carries (e.g Anti-Mage, Phantom Lancer, Spectre, Faceless Void, Terrorblade...) to prevent them from freefarming and owning you in the late game. Get necro if you want to push with your team and end the game early. Necro gives true sight and it's also the ultimate counter to invisible heroes like Riki or Weaver.

- Aghanim's Scepter : Only get it if your ultimate is important enough to be gamechanging. The upgrade is really good on some supports but it sucks on some other ones : for example it's almost core on Ancient Apparition or Visage but you really won't need it on a support Skywrath Mage :)

- dagon : NEVER EVER make Dagon on supports except if you're trolling. It's an item for gankers.

- Rod of Atos, Heaven's Halberd and Orchid Malevolence : they're not completely support items, more like semi-carry items, but they give very useful disables that you may need in some games.

If you're relly farmed you can consider some luxuries :

- Shiva's Guard : It's mainly an item for initiators who jump in the middle of the enemy team and pop this item to slow and damage them. It's great for initiating teamfights if you have a blink dagger/forcestaff. Also counters right-clickers.

- Scythe of Vyse : the ultimate item for intelligence heroes. If for some reason you are sitting on a ton of gold then don't think twice and just grab a sheepstick. The disable is completely gamechanging ; it's your best late game item. get it early if playing against evasive heroes like Anti-Mage or Storm Spirit, it really helps.

- Refresher Orb : Get it on initiators who have a game-changing ultimate with a long cooldown : Enigma, Warlock, Dark Seer, Tidehunter, Omniknight, and...yeah that's essentially it, very few supports need one.

Get those when needed :

- Observer Wards. You should buy them on every cooldown and place them, it's absolutely gamechanging. Supporting is 99% about proper warding, the rest is just details.

- Sentry Wards : to deward enemy observer wards

- Smoke of Deceit : to gank without being seen by enemy wards, or to do Roshan

- Dust of Appearance : always, always carry dust if they have even a single invisible hero.

You can make your picks from the list, and feel free to experiment. Your items won't be the same twice because it's all dependent on the game, your team, and the enemy team.

Hope this helps, cheers!

I am pretty sure that the ethereal state gets dispelled once you start channeling Town Portal Scroll.

However, it works with Boots of Travel.