If you read Zariel's background and current plot that WOTC presents to us, she is a very troubled Archdevil, she faces abnormal civil strife within her own ranks (more so than the normal Archdevil, which must be really bad, if that's being stressed out). That is mostly due to her background, which makes both devils below and above her distrust her (again, more so than the "healthy" distrust between devils).
Yes and no, Zariel is pursuing Karlach because she absolutely must punish her as an example. Karlach is known in hell as a very skilled warrior; her escape wouldn't go unnoticed. If Zariel were to simply let her escape, it could lead to even more escape attempts, something Zariel, given the dire situation, cannot afford. I'm afraid she would do whatever it takes to punish her as a deterrent as soon as she landed back in hell.
Originally Posted by GenPlastro
Furthermore, we know Karlach's heart engine is an outdated model when speaking to the gondsmen at the factory in the Avernus part of the game, which means that Zariel has access to much better troops to send over to the material plane.
That's why, even more so, the solution to her engine problem should be resolved right there. We have experts at hand whom we've saved and who have access to technology that enables the proper functioning of such devices in Faerun. I don't understand why this aspect wasn't resolved right there.
Originally Posted by GenPlastro
Moreover, the people she sent over to capture Karlach in the game are pathetically underequipped, Karlach doesn't really get hunted much more in the game, this implies Zariel might not really give much of a crap about Karlach at all.
Wyll theoretically isn't just anyone. A group of paladins is nothing to scoff at either. Perhaps he's well aware that he won't be able to function for long outside Avernus, and that's precisely why she doesn't send entire legions after her, or perhaps her other issues prevent that.
Originally Posted by GenPlastro
Another clue to her background, we have even the plot about Raphael trying to oust her, which just ties in with her WOTC cannon.
And lastly, as it was already pointed out, Tav stands in a unique position of possessing an extremely powerful soul that Zariel wouldn't pass over, she would likely free Karlach and restore her in exchange for Tav's services and his soul :P
Yes, but we would return to a point where there is no good solution. An arrangement with Zariel wouldn't be beneficial for anyone; I don't think it would be a job contract where Tav kills demons for Zariel from Monday to Friday and then spends the weekend with Karlach.
It's not that these things are impossible. My frustration stems from the fact that solutions are within reach, which the game teases us with throughout the gameplay, only to end by metaphorically slapping the player in the face.
Overall, I have a strong impression that the entire ending, aside from Karlach's storyline, is rushed and underdeveloped compared to the rest of the game. Not to mention the fact that in the second act, I had to switch the game to English because half of the letters/documents/books weren't translated into my language, and instead of text, there were only two square brackets []. But that didn't bother me as much as the utter disappointment with the ending of such an otherwise fantastic adventure in such a pathetic manner.
