Diablo III- Skills Article XLVII: The Demon Hunter, Hunting Skills- Companion

Companion (10 Discipline): Summons a raven that lasts until something kills it and periodically pecks at enemies for 30% weapon damage.

Companion is a bit of a strange skill for the Demon Hunter to have- conceptually, while cool, it makes little sense.  But that’s not what you’re here for anyways, so I’ll get on with it.  The default form of this skill is of very little actual use- the raven’s damage is outright tiny, and it doesn’t attack as often as you’d really like.  The main point here is that it’s kind of a fire-and-forget, a skill you trigger when you enter a game and then only retrigger in the event you’ve been in enough area-of-effect damage zones to cause the thing to accidentally bite it.  The real strength here is in the various runes that alter the skill.

Spider Companion (10 Discipline): Summons a spider that lasts until something kills it and periodically bites at enemies for 30% weapon damage and slows their movement by 60% for 2 seconds.

Marginally more useful than the standard raven companion is the Spider Companion- the slow would be a lot more useful if you could either control what the spider bites or rely on it choosing the target that you most want slowed.  Really, the lack of control is kind of an exchange on not having to really think about the skill- but it’s not a very good exchange in most cases.

Bat Companion (10 Discipline): Summons a bat that restores 3 of your Hatred per second and  lasts until something kills it and periodically bite at enemies for 30% weapon damage.

One of the best options for Companion is the Bat- who gives you constant refill on your Hatred pool.  This benefit is huge, especially if you use up bits of your Hatred pool here and there all over combat.  Even if you focus on dumping all your Hatred at once in occasional bursts, it can still help those last longer- and will make them much more frequent.  Just remember to launch the skill when you enter a game, or you’ll find yourself missing it a lot very quickly.

Boar Companion (10 Discipline): Summons a boar that lasts until something kills it and periodically attacks enemies in a small area for 30% weapon damage.

This isn’t too bad an option for the Companion skill, changing it into a decent way to deal extra damage to closely-clustered enemies.  Sadly, you still have no control at all over the thing, and if your enemies are spread out at all, the area of effect just isn’t going to mean a lot.  If you travel with a Templar companion or have a friend that brings their Monk or Barbarian into games with you a lot, this becomes more useful- but strictly speaking, it’s just not all that great.

Ferret Companion (10 Discipline): Summons a pair of ferrets that last until something kills them and periodically bite at enemies for 30% weapon damage.  As long as they are active, they will race around the screen collecting gold for you, and increase the gold that enemies drop by 10%.

This is the other best rune for Companion.  Not having to chase down gold, ever, and increasing the amount of it is a great improvement on the ‘tiny occasional damage’ effect of Companion, and is really worth the skill slot a lot of the time.  If you don’t need the Bat’s regeneration for your Hatred pool too badly, go ahead and stick with ferrets instead.  Fuzzycute ferret ferret!

Wolf Companion (10 Discipline): Summons a wolf that lasts for 25 seconds and periodically bites at enemies for 60% weapon damage.

The main advantage to Companion is that it’s completely a fire-and-forget skill- unless you find yourself and the area around you getting constantly bombarded with area attacks, the companion is really unlikely to die, since they don’t attract much attention.  This rune is very questionable in value: in exchange for doubling the damage the companion does, making it low instead of insignificant, you have to re-use the summoning skill every half a minute.  At a cost of about a third of your Discipline pool, this is a really poor deal, and despite the more significant damage, it’s almost impossible to gain a serious benefit out of taking this rune.  You should stick to the Bat or Ferret runes if you’re sure you want to use the Companion skill.