This Boatmurdered?
I forgot that was mentioned.
It kinda reminded me that I made an entire campaign surrounding a party going to a mountainhome that was taken by undead with a very OP necromancer residing inside. It thus started a 2+ year game that went through a couple hiatuses due to things like rehab nad such, but it was all on bay12 (I can link it if you're willing to read the buttload of pages). The coolest part of this was I took the dungeon and laid it out like the real fortress it was based off of. The fort? Necrothreat.
It ended with a climatic battle against the necromancer who gained powers from a demon lord to control living shadows. He increased that power farther by using them to inhabit corpses or living things (the former more than the latter). He caused the NPC party member that was a space marine to go batshit insane, indirectly killed a party member, killed one in that combat, and set forth perhaps some of the most epic battles and combats I have ever seen. No where else does a paladin get swallowed by an undead Wurm only to cast turn undead inside its stomach, blowing the monster up from the inside, and the undead horror gets back up with most of his body severed from its head and crushing a party member.
Also, I had all party members be copied in secret by the shadow monsters that the necromancer created as his basic footmen (who were based on DF's boogeymen) and all party members who were slain on the way there were revived and fought at some point in the journey (one bieng a recurring enemy and acting as the field marshal of the shadow and undead army). So the last few battles ended up being against the necromancer's perfection of melding his necromancy with his shadow magic, where he forced the soul out of a body and used its prowess as shadow magic to bolster the body and strengthen it, and this process left an empty shell of a body with a shadow monster inside it, and were literally called Husks, and they had a lot of HP, hit like a truck, and decent defences (they also were immune to stun and prone, but took extra damage instead of getting the debuff). I tried to show them that the shadow monster inside of them didn't fully inhabit the body by having the husks show no signs of the bloodied status and didn't flinch or show any signs of pain on hits and heavy damage. Instead, I got party members destroying entire rooms to kill them.
One of the last battles was a "boss rush" where I split the party member and had them fight party members that they had some sort of significance with (except two, who fought a guy who died in the first encounter) and it lead to a vampire kid pulling a general grevious attack, a confusing maze that took longer than it should, and a guy who used his own head as a flail.
The battle with the necromancer started with party members who, though died, were coming back due to one guy wanting a second chance at his character due to him dying from a VERY bullshit reason, and the other was a rejoining character, along with the clones of the party members who were there PLUS the necromancer. This became one of the most epic fights I have ever seen. The party wizard uses his AOE to the best of his ability and not only knocks the necromancer into magma but whittled down the shadow copies of the party members enough that killing them was a breeze. Two bodies remained when defeated, and in their minds, their god/goddess gave them a chance at redemption; the avenger of Bahamut and the Vryloka Vampire of The Red Witch rose up again and fought the necormancer as he, in a shell made of living shadows, pulls himself out of the magma and forms the second part of the fight: The Shadow Giant. He got a huge boost in HP, some extra attacks and a bonus to some defences, and reach. The party fought him with all they had, and then before the second round was done, his third form started; the shadow colossus. Size huge now, attacks multiple times (3 times now), almost triple his starting HP as the regular necromancer, and his recharge power he never got to use that had the chance to knock party members prone and slide them towards the magma. The party's berserker drops his ultimate attack and crits on his first swing that did 4d12+11 damage, which meant it maximized (4e was weird like that...) and added an extra 1d12+1d8 damage. He then swings again with his daily power that lets him swing twice for 3d12+11 damage. By the end of it, he did 200+ damage, and HE DID NOT KILL THE SHADOW COLOSSUS. Instead, the necromancer put up his final form; the shadow demon form. He grew wings, had about 700hp (this is still the third round and thats total HP, adding about 200 or so hp every form), had amazing defences (nothing under 24), was a 5x5 monster at this point, and the party could physically feel that this still wasn't the peak of his power, even though his influence (which spanned so far that it now affected the place the party started in, which was over a month's travel away) seemed to leave the fortress now. The party fought hard, and the shadow demon released his final gambit; a daily power that did 4d12+12 damage to EVERYONE ELSE in the room. He burst into a hundred spears of darkness before reforming, killing the party's secondary tank instantly, bringing one person to dying status, and bringing everyone to 10%hp or less. The encounter neeed to end. Third turn ends, and then finally, before the necromancer is given a fourth turn, the party destroys his shell, and his power is completely taken from him as the power is sucked into a now active portal behind him, which showed everyone images of the abyss and the sound of chains. The necromacner darted towards the portal, across a bridge, and rapidly aged before the party, turning from a man who was in his mid 30's to a man who was on the brink of his deathbed. The party ranger, who was influenced heavily by his power, crossed the bridge first in pursuit, and brutally slew him, breaking his bones with his fists alone, and turned the old man's face into a bloody mess. He got up and laughed as he was stripped naked by chains coming out of the portal and was sucked in, swearing that he would return from the abyss now that he remembered his full past.
The magma starts to rise, flooding the room. The party dodges falling balls of fire and stone, and escape through a secret tunnel to the surface, and for the first time in weeks, see the sun setting. Laughter is heard as they finally collapse; its over.
And then began their journey back, and on the way, they met an NPC party member who fled them in fear who paid for her cowardice being crippled now. She, being a skald, requests to do the party one last favor before they leave her behind, and she tells the local bar their entire story, granting them each a title and hailing each as a hero for their deeds of ridding this necromancer plaguing the lands for the past generation