How would you prep as a 14th level party to storm the bbeg castle?

[Shallown]

To clear that up the BBEg is the son of Lolth when she was a demon queen before her rise to Godhood. He is Grazz't a Demon prince of Corrosion. He is more about acid then about fire. He isn't the typical Grazz't from D&D past but loosely based on him. Since Lolth was prepared for being cut off from her home plane she has not become weak as Grazzt has, so he bathes every few weeks in a acidic pool somewhere to regain his strength. The players have the location (and map) to the sceptor and crown which may help with the ceremony.

later

 

[Rayne Blythewood]

Perhaps we can alter his little bathing area and make it clean him. I nice big pool of holy water enchanted with cleanse and remove poison. This guys sounds pretty kick ass. Corrosion doesn't sound like something that will be fun to deal with.

 

[Sir Whiskers]

Just had a thought:

The 8th-level spell screen lasts 24 hours, covers a large area, is not affected by SR, and only gives a save if a creature interacts with the illusion. The party could use the spell to hide the fact that they're performing the ritual. The hard part? It's 8th-level and the party are 14th.

Perhaps using planar ally could bring a creature that could cast the spell, or knows how to obtain a scroll of it. Or maybe the party knows someone who can help them (a high-level wizard they can pay to scribe it) - just teleport to the guy, the teleport back with the item.

May not be do-able, but if they can get access to the spell, it may solve the gate problem, leaving just the kids to worry about.

 

[Thanee]

Burrow a tunnel inside. Proceed with plan B.

Or just knock at the door and say you bring the pizza. No, wait, that was shadowrun!

Bye
Thanee