Have you played the module (blind)?  It's not so  much that anything happened at the door, it's that we managed to get it  open.  It doesn't take you long to get paranoid, shaking, and energized  by Tomb of Horrors.
		
		
	 
Not sure I've ever had the pleasure.  If you can call paranoia, shakes, and engergized "pleasure."
	
		
	
	
		
		
			Tarkus was the man villain behind the scenes during the first 2+ years  of my current campaign.   He had been introduced even in the back story  of one of the PC's, and was known to be necromancer  involved in some dark and mysterious work.  All plot threads seemed to  connect to the mysterious Tarkus.   Unbeknownst to my players, Tarkus  had been introduced to them in session 1 of the campaign as the  neighborly undertaker Master Findel who lived beside the parties Cleric.    I had managed to work several conversations with Tarkus into the  game, and at one point they'd even sought him out as a resource - since  he proved 'surprisingly knowledgeable and well educated'.  Tarkus in  turn covertly made several attempts on the life of the party and did  kill one of the Priest's other neighbors, a seemstress, and as his  signature ability was known for summoning large numbers of Hell Hounds  (which at one point involved a chase over the roof tops of the city as  the party fled a pack of hellhounds).  Eventually however, their  suspicions regarding Master Findel awoke, and investigations  lead to a series of increasingly violent confrontations and eventually  fireballs and small armies of the city guard.   Tarkus managed to escape  each encounter, however the party learned Tarkus's motive and means.   He was in the city on the behalf of the even more mysterious Keeropus to  obtain from the Lower Catacombs, indeed from the tomb of a Menes III, a  sample of Dark Fire to be used in powering the still mysterious engine  Keeropus was known to be creating.  This was the same Lower Catacombs  where at a sealed entrance they'd discovered a rune warning that behind  this seal lay necromantic hazards that poised a threat to the very  existence of life.    To this end Tarkus had arranged over the course of  the prior two years to tunnel into the Lower Catacombs, and was now  searching for the Dark Fire in their labyrinthine depths.   The party  attempted to head him off by finding the dark fire first, encouraged and  aided in this plan by their contact the Wizard Master Aiden who served  as a sort of 'fix it' man for His Benevolent Despot Falster Dikelgard.    Long story short, after several forays into the catacombs, the tomb of  Menes the III was breached and the dark fire extinguished just minutes  ahead of Tarkus.  Tarkus - unaware that his quest was now futile -  proceded to engage the party in an epic fight involving Hell Hounds, Juju Zombies, and fiendish wolves (and fireballs and various necromantic nastiness) that resulted in one PC death and which only avoided a second by the expenditure of a destiny point and timely divine intervention in the form of an angel of Showna (the Sun goddess) before finally taking a sword through the back  as his pets were beaten down.   In short, I managed to pull off the  sort of epic reoccurring villain that I'd been striving to pull off  (without cheating mind you) since I was a kid and much high fiving and  hooraying occurred.
		
		
	 
Can Modos do it:
Necromancer: yes, that's just a spell selection question.
Summoning Hellhounds: I'll include Summon in the original spell selection.
Investigations: Detect, Knowledge-Scholarship, or Profession skills would help.
Dark  Fire: sounds like a magic item.  Modos magic items are currently  granting character features (ability, skill, or perk) to characters, or  acting, mechanically, as NPCs.
Mysterious engine: there are no  movement rates in Modos core.  So the speed of the engine, and what it  could do, would be up to the GM.  However, when things are difficult to  damage (like armor), they have Protection, which is a die that reduces  incoming damage.
Juju Zombie and Fiendish Wolves: the new rulebook will have a section on creating monsters.
One PC death: Modos doesn't have dead PCs.  The closest a PC can get to death is Mostly Dead.
Destiny point: hero points.  Roll 1d6, in most cases, to gain a skill bonus.
Divine  Intervention: no rules for that beyond rule 0.  I don't want to include  incorporeality rules, but it could be fun to draw up a monster or two  with that feature.
Sword through the back: no hit location in Modos,  but there will be guidance that crippling wounds don't happen until a  character is very low on, or out of, hit points.
Thanks James...your input's next on the examination table!