Gives a lot of stats that casters & supports would like. Many of them are lacking in HP Regen and Armor. The INT is a bit of a bonus.
It's a supportive item in nature, but can be ok on magic damage dealing semi-carries.
I feel the reason you don't see this often is because:
- Most teams don't have a magic dealing carry
- Most supports pick up other utility items (e.g. Mek, Force Staff)
Who to Get This On
The item can be good on many heroes. Armor is good for anyone, but especially for heroes in the middle of the fight.
I'd cluster it into groups of:
- Jakiro - he has a lot of spam to offer, adds to his natural tankiness
- Crystal Maiden - she has low Armor and barely any HP Regen (excluding item pickups like Tranquil Boots). Combos well with her ult (provided you manage to get it off).
- Shadow Demon - Shadow Poison can hit a huge group and does a ton of damage
- Lina - lots of AoE magic damage spam and a huge magic damage ult
- Keeper of the Light - combos well with Illuminate, which already does an absurd amount of damage. KotL is very squishy and lacks HP Regen.
You might consider it on heroes like
- Ogre Magi - though you're mostly single-target, Ogre Magi has huge potential to insta-kill a target with lucky multi-casts. This item also adds to his naturally tankiness.
- Lion - another hero that is basically single target. Not really worth getting on him, but could be situationally good.
- (Support) Gyrocoptor - big AoE ult that's pretty reliable to combo this with. Gyro is naturally very squishy lacking in HP Regen.
- Venomancer - another squishy hero. Combos well with many of his spells (namely his ult). A bit more achieveable than an Aghanim's Scepter if you're playing support.
- Disruptor - Combos well with your Ult. However, getting a good combo off isn't guaranteed. Gives Disruptor many things he needs - mana pool, HP Regen, and Armor.
- Lich - combos well with a GOOD ult. Lich lacks HP Regen, and it gives him armor that's not conditional (i.e. Frost Armor spell)
Semi-Carries & Carries
- Leshrac - there are arguably better items for a Carry Leshrac, but as a heavy magic damage dealer that needs to be close to your targets, you can get a lot out of Veil of Discord.
- Zeus - you're squishy, deal a lot of magic dps, and you have virtually no HP regen (minus Bottle). All around pretty good and more affordable than an Aghanim's if you're struggling
You might consider it on:
- Pugna - Netherward deals a lot of damage (and I believe it's Magical). Pugna has a lot of magic damage besides that, Netherblast and his ult deal tons of magic damage. I'm not 100% sure, but I believe this item stacks with Decrepify.
- Outworld Devourer - Not very useful for most of your spells, but can work with your ult. I wouldn't say it's very useful in general though.
- (getting it for) Meepo - while I wouldn't get it ON Meepo, getting one to support him early-mid game could be useful due to the damage output of Poof
- Necrolyte - basically the same as Leshrac, however, your magical DPS is not as high. I'd say it is more situational on Necro.
- Sand King - you have a lot of controllable magic damage with your ult, however casting the debuff might be tricky. If you cast before ulting in, you might tip the other team off. If you wait, you might forget, get stunned, or miss out on some damage. You're still going to want to prioritize your Arcane Boots & Blink Dagger first (unless you have other setup)
- Enigma - Your ult & midnight pulse should both benefit. Works well if you get the enemy team in a black hole and other heroes can cast on top of that. Getting all of your spells off + this item is tricky though.
Might consider it on:
- Puck - you are a magic damage initiator, but I don't feel like it is necessarily worth it to go this route. You already have to get in and out of the fight quickly being squishy and don't have much time in your Blink + Ult + Silence + Orb combo.
- Earthshaker - your damage is situational (based on nearby units), but can be a decent addition to your items after your core.
- Warlock - Combos well with your Ult. However, Fatal Bonds is damage removal. Really not too worth it unless you have more spells to combo from other heroes.
You could make arguments for heroes like Queen of Pain, Tiny (when you're not playing him as a carry), Tidehunter, Magnus, etc. But I think their money could usually be better spent elsewhere.
When to Get This
The timing on when to get this item is kind of odd.
- It's great for team fighting
- It loses some of its power after your opponent picks up BKB or Pipe
- Spell damage hits its peak around level 16 (late game, heroes have magic armor, tons of HP, or can insta-kill you; many spells don't scale well into late game)
The item becomes increasingly effective with the more "Wombo Combo" your team has (e.g. Sand King Ult into Jakiro Macropyre and a Warlock ult in there somewhere).
I think more often than not, you're going to find this to be a luxury item. Most teams don't have enough (or coordination for) Wombo Combos. It has a short enough cooldown that only hitting 1-2 opponents would be worth it. But, you also have a lot of items that are more beneficial, like BKB, Mek, Force Staff, etc. Magic Damage has plenty of ways to counter it (e.g. BKB, Pipe).
I feel the main times you'd really want this are:
- Rushing it on a ganker/initiator to gain early game control
- Getting it early-mid game on a Wombo Combo team
- Getting it later on when you're looking for a 3rd or 4th cost-effective item on a hero like Sand King