What exactly are core heroes Dota 2?

 

For example I know heroes like Kunkka, Tusk, Invoker, Queen of Pain,... are called "core". Why are they core and not carry and what exactly are they supposed to be doing in the course of the early/mid game? What about semi-carries? In general, how to tell which hero is good at carrying and which is not so good (other than reading a guide and memorizing every single one's roles)?




The cores are simply those heroes that take priority in farming, with the idea that levels/items in them are going to make a difference in the match. Take into account that the same hero can be played as core, and as support.

For example, a core Tidehunter will try to farm a quick Arcane Boots + Blink Dagger, so as soon as he hits level 6, he becomes a dangerous threat to the enemy team, exploiting the other's team lack of Black King Bar at that early, forcing fights and taking early objetives.

If you were to play Tidehunter as support, you'd be expected to excel at good positioning and judgement to use that ultimate, probably because your team is not as interested in early fighting, as it would be in having a counter fighting option.

Building on this, a 'hard carry' vs. a 'carry' vs. a 'soft carry/semi-carry' vs. a 'core' depends on what they build towards and how early they can be useful.

Carries

Carries are heroes that will do well late game with large amounts of gold and levels, but kind of suck early on. Generally, they have abilities that make that farm do more on them than another hero and generally those buff their right click damage (there are exceptions to this). For example, Anti-Mage has a low Base Attack Time, so he will hit more often with the same amount of IAS compared to say, Tidehunter. Faceless Void and Slardar have bashes that stun on attack. All of them scale very well with items.

Semi-Carry

A semi-carry will have abilities that are strong early, but some ability to scale with farm. They won't have as much scaling as a hard carry, though. Even just being a ranged AGI hero can often be enough to make someone a semi-carry. Mirana is the classic example, and she's been played every position from 1 to 5. Semicarries usually need to be snowballing to stay relevant lategame though, as they taper off when things go late.

If a hero has a skill that buffs their right-click, they're often a carry, or CAN be played as one. Carries also frequently have a means to accelerate their farm, (or they buy one). Anti-Mage ( Mana Break, Blink , 1.4 BAT), Slardar (Bash,  Amplify Damage), Drow Ranger (Precision Aura, Marksmanship) and Naga Siren ( Mirror Image) are examples.

Hero can snowball hard early and get powerful damage items

If a hero can snowball hard early and get powerful damage items and put them to good use, they are often semi-carries. Many heroes that like Armlet of Mordiggian, Drum of Endurance or Desolator fall in this category, as they offer tons of midgame power for little gold. Sven, Mirana, Razor, Legion Commander, Night Stalker, Queen of Pain and Bloodseeker are examples.

Right click DPS

Heroes that focus on utility or initiation power usually aren't built as carries with lots of right click DPS, but instead build utility like Blink Dagger, Scythe of Vyse, Refresher Orb, Aghanim's Scepter, Mekansm, etc.Dark Seer , Tidehunter, Enigma, Shadow Shaman, Warlock, etc. can all be played in this role.

Simply get very little from farm

The position 4 and 5 supports are usually heroes that either don't need farm to be effective, but can make use of it, or simply get very little from farm. Witch Doctor and  Shadow Shaman are an example of the former (both get huge ulti buffs from Aghanim's Scepter), and poor Crystal Maiden an example of the latter. Sure, she can build a Scythe of Vyse and get good use of it, but any hero can do that (and most of them can get it online a lot easier).

Most heroes can be played in multiple roles and many heroes blur the lines.

For example, you'll often see Naga Siren played as either position 1 hard carry or position 4/5 support. Mirana literally fits any position (which is why you see so much or her in The International 4, a Mirana pick doesn't paint you into corners). Leshrac can be played as support to push and stun, or as a farming carry to maximize his AoE damage from Pulse Nova. A number of the Intelligence carries use powerful spells rather than raw right click such as Necrophos, Death Prophet and Leshrac.