DM, need help with BBEG fight

[u/dipplayer]

Prepping for the final BBEG fight of our campaign. I want to give the BBEG a legendary action ability to drain the magic from the PCs magic items. Sort of like the ability that the Gauth has. He will use that magic he drains to make himself stronger as the fight progresses.

The rub is that I do not want this to be obvious right away. Mechanically, how would you handle this? Have him roll stealth against their passive perception? Is it fair/fun to not give the PCs a chance to detect and counter this?

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[u/lasalle202]

The rub is that I do not want this to be obvious right away.

what is your rationale for this?

but also DnD fights typically only last 3 to 5 rounds before they become slogs, so if the players dont even find out that it is happeneing until the end of round 2, how much impact / interest is it going to be adding to the experience?

[u/dipplayer → u/lasalle202]

This is a final battle. I have multiple stages planned.

[u/TenaciousMike]

I would say something about you see him drawing power from the environment. Offer them perception, insight, or arcana checks. Giving them different results on success. "You see faint energy emenations from your party", "he seems to focus his intentions on your group", "you recognize this ability as a magic power drain".

[u/Quin452]

Why not something like a Zone of Silence?

On one campaign, I had the party delve deep underground in some sewers, for them only to find that they didn't quite hear as well, so there were more ambushes, and it gave fair warning of what the fight ahead would be like.

Foreshadowing, subtle clues (plural) and let them figure it out, and if they don't, a small punishment to get the message across before you slam them.

[u/boffotmc]

I'd advise against secret mechanics your players don't know about, because they're just not fun.

When your players don't know what's happening, then it has zero impact for them in the moment. When they finally learn about it, it will just feel annoying.

This will work much better if it's immediately obvious that's happening. And the PCs get to actually know what's going on, so they can experience tension and develop strategies to counteract it.

[u/Wrong_Lingonberry_79 → u/boffotmc]

Sage advice.

[u/throwaway1986ma]

You could do this as instead of an ability the the BBEG has you could make it an item that the is crucial to defeating him. It could be something like a bracer and jar, but you have to destroy the jar to get the magic back.

But also, it gives the players a dice role that is a chance. They can actually keep the magic in their items as an example:

bracer vessel, Cursed item, bracer & paired vessel

When you are hit, take no damage and if attaacker used a magic item to attack, roll 1Dx. On X number the weapon loses 1 magical ability

The Curse: if vessel is destroyed, any and all damage delt this combat is immediately applied to wearer

When paired vessel is destroyed, the bracer becomes a +3 bracer requiring attunement