Support heroes are essential members of any DotA team game. These heroes either disable enemies or boost allies with their skills.
The good news is that, any hero with the right items can do the role of a support character. However, some heroes have skill sets that are already optimized for the support role. They have more defensive abilities than offensive ones.
Supporting skills typically fall under four categories. They are:
Disables and Slows
These are skills that disrupt the enemy heroes which causes them to become vulnerable for attack or give allies enough time to escape safely.
Negative Buff
These are abilities which removes buffs placed on enemy heroes. It can also be skills which lower the base armor of opponents or amplifies damage they receive. Other skills such as Mana Leak causes heroes to lose mana points.
Positive Buff
These are skills that boosts the abilities of allied heroes, usually increasing their damaging abilities. Some positive buff skills also include increasing armor, movement speed and rates of restoring health and mana points.
Heals
Obviously, this skill simply gives allied heroes additional HP during the game. Mekansm is an example of an item which support heroes usually get. Aside from giving health points, healing can also come in the form of giving rescue to low HP allies through teleportation or wind walking abilities.
Items that are usually used by support heroes include Guinsoo's Scythe of Vyse, Eul's Scepter of Divinity, Assault Cuirass, Mekansm, Nathrezim Buckler, Headdress of Rejuvenation, Bloodstone, Shiva's Guard, Diffusal Blade, Vladmir's Offering and Orchid Malevolence.