Kaletar

Many people in the comments do not seem to understand how this follower works. This might be due to the description of her ability being false.
Kaletar is definitly one of the better Venthyr units and in some situations one of the best overall healers ( so far, Renown 21 ).
Most healers have a direct heal with a 2-3 round CD with an overall greater heal output. So why is Kaletar good?
Abilitys are activated at the start of each fight. If your followers are full health ( which they should be and probably are when you do a hard mission ) the first cast of almost any healer will be totaly useless since it will just overheal your team.
Kaletar's heal however is a heal over time effect. It will heal your entire team for a low amount every single round. This is crazy good against enemys that spread their dmg well with abiliys, or have a mixture of melee and range fighters.
It is weak against heavy single target damage but so are most healers. A self-healing tank would be better in that situation

Sadly she is kinda useless, her heal is meaningless and doesn't seem to scale well with her level.

Here is my strategy for collecting the companions available in Torghast. I got this information
from reading your posts on wowhead and some other websites.

First of all, I want to start out with this info:

Possible Companions from Thorgast for Night Fae:

[npc=171968] [Humanoid] [Any Layer]
[npc=171969] [Elemental] [Any Layer]
[npc=171971] [Humanoid] [Any Layer]
[npc=171972] [Humanoid] [Layer 2+]
[npc=171967] [Humanoid] [Layer 3+]
[npc=171970] [Humanoid] [Layer 3+]

Possible Companions from Thorgast for Necrolords:

[npc=173745] [Undead] [Any Layer]
[npc=173744] [Undead] [Any Layer]
[npc=173743] [Undead] [Any Layer]
[npc=173740] [Undead] [Layer 2+]
[npc=173741] [Undead] [Layer 3+]
[npc=173742] [Undead] [Layer 3+]

Possible Companions from Thorgast for Kyrian:

Hala [Humanoid] [Any Layer]
Ispiron [Mechanical] [Any Layer]
Molako [Humanoid] [Any Layer]
Kythekios [Humanoid] [Layer 2+]
Telethakas [Humanoid] [Layer 3+]
Teliah [Humanoid] [Layer 3+]

Possible Companions from Thorgast for Venthyr:

Nerith Darkwing [Humanoid] [Any Layer]
Stonehuck [Humanoid] [Any Layer]
Thela Soulsipper [Humanoid] [Any Layer]
Kaletar [Humanoid] [Layer 2+]
Ayeleth [Humanoid] [Layer 3+]
Dug Gravewell [Humanoid] [Layer 3+]

Possible Companions from Thorgast for all Covenants:

[npc=165562] [Humanoid] [Any Layer]
[npc=165537] [Humanoid] [Any Layer]
[npc=169842] [Humanoid] [Layer 4+]
Croman [Humanoid] [Layer 4+]

From my experience, when you are on Layer 5 of Torghast (any wing), floor 1 in Torghast will contain one or more of the following:

1] A rare elite
2] A treasure chest
3] A campaign mission companion
4] A non-campaign mission prisoner
5] A special visitor

The first 4 reward an anima cell, but the special visitor has a different reward.

Examples of a special visitor:
The Lost Dredger can let you into a secret portal to get more phantasma.
The Maldraxxus Skeleton will give you a thrill ride through a Torghast floor run.

Non-Campain mission prisoners:
Indri the Treesinger (Night Fae)
Indigo (Night Fae)
Moriaz the Red (Necrolords)
Bloodletter Phantoriax (Necrolords)
Sawn (Venthyr)
Renavyth (Venthyr)
Calix (Bastion)
Gallath (Bastion)

If you are on a floor with any of the special visitors or the non-campaign mission prisoner's, there
will not be a campaign mission companion on that floor.

What I was mostly interested in was acquiring the campaign mission companions.

My method to obtain the mission companions involves using the Layer 5, Floor 1 technique.
Currently you can enter Floor 1 of any Torghast wing, do your thing, exit Torghast, and
repeat, since there is no limit to how many times you can enter and exit Torghast.

Your focus should be only on Floor 1. If your companion is not there, wash, rinse, repeat.

Next, I want to talk about your strategy for all classes.

If you want to get any of the first 3 companions in each list of 6 (the ones that are available for "any layer") I suggest sticking with
Layer 1 of any Torghast wing to make things easier.

However, it has been my experience that the higher the Layer, the better chances you have of finding a companion. With this
being said, I recommend using Layer 5, that way you can get all of the companions.

Next, I want to talk about your strategy for specific classes.

1] Hunter : As a BM Hunter you have 3 things working to your advantage.
A] You have a "Hunter Tracking" ability that puts dots on your mini map to show you what type of enemy or friend is in the near
vicinity. Red dots are enemies, green dots are friendly. You are looking for green dots. In most cases you are looking for humanoids
(or undead if you are a Necrolord), but a couple of exceptions are mechanical (Ispiron) and Karynmwylyann (elemental).
B] You have "Camouflage" + "Eyes of the Beast" that will let you travel around the floor looking for those green dots.
C] "Play Dead" and "Feign Death" to get you out of trouble.

2] All other classes you can eat food "Blackened Worg Steak" [item=42997] to track humanoids.

3] Rouge : As a rouge, you will stealth around looking for trapped companions. Vanish if you get in trouble.

4] Warlock : "Eye of Killrog" to look for green dots.

5] Shaman : "Far Sight" to look for shackled companion's.

6] Mage : "Shimmer" and "Invisibility to look for green dots.

7] Druid : Cat form stealth to look for green dots.

8] All other classes, I don't know them very well, so you tell me what works good.

Next, let me talk about the Runecarver messages when you enter Torghast Floor 1.

When you enter Torghast Floor 1 and you get a message from the Runecarver:
Runecarver says: Even a Harvester of pride does not deserve to languish here. Save the venthyr from this fate.
It could be your Venthyr companion. Go find it.

Runecarver says: "The brave... the mighty... the treacherous. All are bound here. Free them."
It could be your Necrolord companion. Go find it.

Runecarver says: "A lost fae, bound in torment. Free them... lest they be consumed by darkness."
It could be your Night Fae companion. Go find it.

Runecarver says: A child of Bastion... undeserving of such a fate. Lead them into light.
It could be your Kyrian companion. Go find it.

When the Runecarver says nothing, there is a chance that you might be on a floor with one of the 4 companions that
are available for all covenants. Look for a green dot.

If you only want your covenant companions, the Runecarver message can be your determining factor as to how you proceed.
If you do not get the Runecarver message for your covenant as soon as you enter Torghast, exit Torghast and come back in.
However, it might serve you well to go just a little bit deeper into the floor before you decide to exit.

Another thing is to zoom in on your mini map. I typically always have my mini map on full zoom out, but for this you may want to
zoom in a couple of tics to spread out the red and green dots that show up.

So far I have successfully obtained every companion for my covenant (Night Fae) and also Croman and Meatball using this method.
I still have yet to obtain [npc=165562] and [npc=165537].

I hope this information helps you, good luck on your journey, and feel free to share comments.