I recall that trigger being kind of finicky. It can glitch via canceled conversations (accidentally clicking somewhere that causes the PC to move), walking too fast past the trigger so that the convo starts and then quits before you realize it's going, etc. And, once triggered, the conversation often marks itself as done, whether or not your finished your business with Enserric.
In Myriokephalon's case, it sounds like the trigger has already fired and quit before you got a chance to talk to it. Unfortunately, the objects the variables are set on aren't the PCs or the module, so I don't think there's an easy way to trigger the convo from the console without scripting. Last time I played, I had this trouble and wrote a very short script to reset the trigger from the console using
dm_runscript
. If you are having the same problem I was, I can send it to you. Obviously, if you aren't interested in having the conversation itself, you can just beat up the dead kings and use the console to create Enserric directly.
BTW, I like Enserric. The first time I played HotU, I mostly missed his antics because I was playing a wizard who rarely used a sword. And, I was annoyed that the on-hit talk property and visual effects counted as item properties when Rizolvir is deciding whether your weapon is already too magic to add anything to. But, the other time I played, my partner was a melee character who used Enserric the Greatsword as her primary weapon. It can be repetitive sometimes when it triggers too often, but he has quite a bit of dialog (on-hit shouts) and he kept us chuckling all the way through HotU and then through Sands of Fate. (And, I changed the code that counts item properties to ignore class/race/alignment restrictions and things like visual effect properties.)
