D&D 5E (2014) Help Me Create an Epic Final Boss Fight!

[jayoungr]

The spirit is bound to the clay vessel. What happens if the clay vessel is destroyed? Spirit unbound and free?

Yes, that's what happened in the previous case. If that happens ... sequel adventure! However, the other spirit had actual mind domination abilities. This one would have to try to trick or persuade someone into destroying the vessel.

What happens if the clay vessel is mended with the spirit on the outside?

The current situation continues: spirit outside but unable to move. The PCs would have to carefully crack the vessel again.

Which character has the mending spell?

Both the bard and the barbarian have it. (In this setting everyone gets three cantrips for free.)

Does the spirit know this?

No, the spirit has no way of knowing this.

If the only things the spirit can summon are undead that can be effected by the artifact, it greatly diminishes the power of the spirit.

This is so, but the entire campaign has been about assembling the pieces of the artifact, so I also don't want to nerf it. I was thinking of compensating with sheer numbers of enemies (which would also provide handy targets for that necklace of fireballs). I was also thinking of having some stronger summons with advantage on saves against the artifact. Maybe some of the smaller ones could combine into stronger ones, like oozes?

On the other hand, if the spirit can summon something(s) that can detect the artifact and attack the character carrying the artifact, could force the party to defend that character. Or maybe the spirit could summon something that could steal the artifact from the character.

These are also good ideas. The artifact is a bell, by the way, and spirits are said to be affected by its sound. So if the spirit can prevent the bell from being rung, that is to its advantage.

 

[aco175]

It seems like the big bas should be CR 15 or so, but has a power that can be turned off making him about CR 12 after. There should be some mass of mooks that draw attention or split the party to have to deal with them. They should be one or two hit monsters. Perhaps a third group or item that powers the whole area that can be turned off to make things easier.

Maybe there are 3-5 'stones' around the town in a pentagram or something that glow and can be disabled like a trap. This stops the mooks from spawning each round. The mooks arise maybe 2d6 each round in a couple locations. Some should be able to reach PCs this round and some the next. This allows them to move in reaction to the PCs.

The big bad can have an aura that can be turned off. Maybe a half damage thing or disadvantage within 60ft. There can be a magic way to turn off for a few rounds or longer. Maybe it is concentration allowing a few rounds to get the upper hand.

either option allows for the BBEG to become weaker and if both are done, then the battle should swing to the PCs.

 

[jayoungr]

For enemies that are unaffected by the bell, someone on Discord suggested that maybe the spirit or its minions could animate piles of debris.

 

[Moving Pictures]

How long does the bell's effect last?

 

[renbot]

What kind of action is it to ring the bell? A one-round turn undead that takes up someone's Action would keep it from being an encounter-killer. And the baddies could target the bell wringer who would then need to be protected.

Also, I was imagining some sort of sound-muffling creature or effect. Not a full Silence effect, but something that limits the range of the bell's effect. Mist/fog and sound muffling are pretty common fantasy tropes so it shouldn't seem needlessly contrived.