I'm a die hard Summon/Combat Pet fan, always have been, but even I can't justify using this morph... it's designed for doing damage, but fails at outputting anything of note while also providing a big fat zero utility to the user. It needs changes badly.
Just look at it:
Call on Azura to send a twilight tormentor to fight at your side. The twilight tormentor's attacks deal 1400 Shock Damage plus an additional 18% damage.
Once summoned, you can activate the twilight tormentor's special ability, causing it to deal 50% more damage to enemies above 50% Health for 15 seconds.
The twilight tormentor remains until killed or unsummoned
Now compare that to the other morph of Winged Twilight:
Call on Azura to send a twilight matriarch to fight at your side. The twilight matriarch's attacks deal 1400 Shock Damage plus an additional 18% damage.
Once summoned, you can activate the twilight matriarch's special ability, causing it to heal the matriarch and up to 2 other friendly targets for 4000 Health.
The twilight matriarch remains until killed or unsummoned.
The first thing you should notice is the Matriarch and Tormentor do the same base damage. 1400 Shock, +18% of that, +whatever scaling you have. They both attack relatively slowly, and their DPS at this point is the same. The only difference between these two morphs is their active abilities, both of which cost magicka to activate once they are summoned.
The Matriach has a scaling heal that heals itself, and up to two other targets (including the user who summoned it). It scales really well and is a great heal all around, and works anywhere you would want it to: PvP, duels, Dungeons, Trials and is especially effective in solo play (since you'll always heal yourself). It's just really great, and the Matriach continues to putter along doing its own DPS as it goes.
Enter the Tormentor. It doesn't provide utility in any shape or form, it does DPS and nothing else. The problem with that is its active ability just plain sucks: 50% more damage to enemies above 50% health for 15 seconds. You may think 50% is a lot... 50% is a lot, but 50% of rather low DPS is also rather low meaning you're not actually gaining much damage. You also have to take into account how slowly the Twilight morphs actually use their attacks, within those 15 seconds it has only attacked about half a dozen times. 15 seconds run out, you've got to spend Magicka to empower it again, and again.
If that wasn't enough, this damage is not without a string attached: the target HAS to be above 50% health for the Tormentor to be able to empower it's attacks. As soon as it hits 49% HP or less, your Tormentor no longer has an active ability. You'll can spend all the magicka you want using the active, but it won't actually do anything until you get a 50% HP or higher target. Think of all the times you'll be fighting something, anything, and it drops below 50% HP. You can only win said fight by reducing that HP to zero, so it is going to drop below 50% at some point. Think about how long you can spend in that health range though. Say, every single Dungeon/Trial/World/etc Boss that exists in ESO. For half the fight its enjoying +50% damage if you keep the active up, and then suddenly half health appears...
the Tormentor is now doing the exact same DPS on the boss as the Matriarch would be. Until the boss is dead or you find another target, your Tormentor has no active ability anymore. Sure would be nice to have something that could heal then, no?
Which brings me back to earlier: the Twilight Tormentor morph is just bad. Really bad. It's active ability only functions for half of any given fight then stops existing, and it's DPS is the same as the healing-focused Matriach outside of the active ability. The DPS advantage it actually has, technically speaking, is barely noticeable due to the low attack speed of Twilights as a whole. As a result, the argument for ever taking Tormentor over Matriach is not a strong one, if it even has a single leg to stand on. Between
+50% of low DPS for maybe half the duration of a fightand a
wonderful group heal available 100% of the time and identical DPS otherwise... why would anyone ever take Tormentor?
Now of course, I don't think it should be this way: Familiar has two distinct morphs, one specifically for damage (Volatile) and the other specifically for "tanking" (Clanferr). Lightning Antronach's two morphs are a tradeoff between single-target and AOE damage options. Twilight remains the odd one out with an amazing healer morph and a DPS morph that can't really DPS. The intention is correct, but the execution is just not right. Tormentor needs something to set it apart, and at this point it could really be anything other than heals.
Tormentor could have higher base damage or higher +X% scaling
Tormentor's current active could be made a passive part of Tormentor and give it a Familiar-Pulse like damage active
Tormentor could apply a debuff to targets it attacks (could even be a random debuff)
Tormentor could provide a buff allies nearby (could also be random)
Tormentor's active could cause its attacks to AOE chain to other targets nearby the first target
Those are just some quick ideas, but really there's a LOT of options to make Tormentor better than it is. And we should make it better, because it's just one of those morphs that... it's really not an option. You could take it, could use it. But for at least half the time you'd be using it, Matriach would be a flat out improvement because it's active can be used anytime and Tormentor's cannot. Even just removing the health restriction and allowing Tormentor to be buffed anytime you have enough Magicka to do so would be a HUGE DPS buff.
I really want combat pets to be a valid option, and after a lot of changes most of them are actually in a pretty good place (outside Volatile Familiar overperforming after bugfix): but Twilight Tormentor is still incredibly flawed, and should be fixed. If not buffed, rework the morph entirely. It's existed for what, years, in this state and I still haven't found anyone who praises it or actually wants to use it. It has the potential to be so much better.