Assassins are focused entirely on damage. They may have some utility skills, but your job is to dish out as much damage to enemy heroes as possible. Some of them have very low health pools, and if a hero is listed as "Very Hard," it goes doubly for an Assassin.
- Best damage dealers:
Valla, Raynor. Very simple to pick up, but exception sustained damage. You'll put serious dents in the enemy team simply auto attacking at the back of fights. They both have access to a stun/interrupt, and have a good skillset for the role.
Warriors are the strong, durable heroes. They have higher health pools than the other roles, tend to gain health regeneration at a higher rate on leveling, and have skills suited to being in the thick of battle.
- Best front line "tanks":
Stitches, Arthas. Powerful health regeneration, talents and skills to keep you on your target, and self healing to keep you in the fight while sustaining heavy damage.
Specialists are weird. You can look at them as a group and say, "OK, well, most of them are based on siege damage, right?" But that's not entirely true... The best way I can describe Specialists would be "heroes Blizzard didn't want to make a new label for." They have summons, debuffs, skills with bonuses against minions and buildings, that sort of thing. For now, think of them as siege heroes.
- Best Siege Damage Heroes:
Azmodan, Sgt. Hammer. They both have the potential to end the game on their own if left alone (you won't be), but do so in different ways. Sgt. Hammer is all about auto attacking from long range, and Azmodan relies on armies of summoned demons.
- Some Exceptions...:
Nazeebo is an awesome hero, especially for a new player. He really doesn't belong in the Specialist category, as he's much more akin to an Assassin based on his skillset. The thing is, all of his abilities are area of effect, rather than targeted, so he can't, strictly speaking, send his spiders or frogs at one person in a fight, but he is a very strong hero in team fights. Murky is - well, just leave him for now. He has a very strange playstyle and will often be a hindrance to your team unless you're making plays alone.
Support heroes are usually focused on shielding and healing. The degree to which they heal you vs. provide utility varies pretty greatly. They have a large mana pool and a good deal of regeneration to keep you casting. You want to stay out of danger and keep your allies alive and protected. You can't support anyone if you're dead, right?
- Best Healers:
Malfurion, Rehgar, Uther. Each of them can dish out insane amounts of healing power. You'll also find these heroes have good offensive skills to protect your allies as well, keeping the enemy at bay.