It's hard for me to believe that the Thalmor's hands stretch as far as to manipulate Black Marsh's affairs. Plus you say that Thalmor agents could unknowingly use the doped-up Argonians to their advantage? How could they do it unknowingly?
I haven't read Lord of Souls yet, so I don't know if there's any information about why the Hist worked with Umbriel, but it seems doubtful to me, that the Hist would be manipulated by the Thalmor along with being manipulated by Umbriel.
Your argument also relies on the idea that both the Hist and Argonians can be easily controlled, and controlling the Hist seems like too mammoth a task for anyone. By the way. Does Lord of Souls ever explain why the Lilmoth tree cut itself off, or if it was the entire Hist that worked with Umbriel?
well lets just say the hist were compromised, in a manner of speaking. it wasnt exactly umbriel but it had a lot to do with it.
there was an evil sabotage done within the an xhileel..and others, as well as the hist.
so no, morrowinds invasion by the argonians is still somewhat a mystery. We do know that part of its reason was that it was an act of vengeance, however that wasnt the whole reason.
when these things manifested is a matter of debate, as far as the rogue hist and the conspiracy within the emperor's hierarchy.
im glad many of you feel the argonians were justified, however given the circumstances it was just more bloodshed for ambiguous,(and from that standpoint one could argue immoral) reasons.
i see it as pointless slaughter. i give skrim at this time a lot of credit for at least offering solstheim to the dunmer refugees with open arms. regardless of whether geographically solstheim lies with skyrim or morrowind is moot. skyrim diffused and avoided a lot of tension in that simple act.
i dont want to dismiss the idea of thalmor tampering. given their intelligence it would be reasonable that they were informed of a way of corrupting, isolating, or manipulating the hist, and so do the same to groups and factions of argonians. it wasnt a matter if they could. its a matter of if they did seeing as it had already been done.
lord of souls is a great read. i would recommend reading it to any tes fans.
this all cant be blamed on vuhon, or hierem, sul or the anxhileel or the thalmor. its all a very complex web.
i stand firm in saying the invasion of morrowind was one of the first great acts of evil of the fourth era.it did far more harm than good.