D&D 5E Targeting Their Attunement

[GuardianLurker]

The only real problem I can see is if your more powerful monsters have a "requires magic to damage" flag set; then things get really nasty, as every attack is a sacrificial one.

Also, to counterbalance the table-flipping, you might want to provide "Ancient Magics" item versions of their gear - perhaps with their appearances remixed. The trait might looking something like:

Ancient Magics: A magic item with this trait cannot be attuned if the character is also attuned to a non-Ancient Magics item. When attuning an Ancient Magics item, the character takes 1d10 damage unless they succeed at a DC 10 Charisma saving throw. If they succeed at this saving throw three times in succession, they no longer take damage from this item during attunement.

 

[CleverNickName]

The only real problem I can see is if your more powerful monsters have a "requires magic to damage" flag set; then things get really nasty, as every attack is a sacrificial one.

And even that isn't much of a problem. Most magical weapons don't require attunement, and there are plenty of cantrips and low-level spells that can turn ordinary weapons (or sticks, in the case of Shillelagh) into magical weapons. Yes, it means the paladin will have to go without his favorite toy until they take a short rest, but that's a minor inconvenience for 10th and 11th level characters. They take short rests after every other battle.

I like the idea of having different "flavors" of magic item attunements, too. I might implement something similar, to help reinforce the 'things work differently here' vibe that I want this adventure to have.

 

[el-remmen]

Most of my magical weapons in the 5E era have been +1 or +2 weapons that grant some bonus ability if you attune to it, otherwise, just a vanilla +1 Longsword, or whatever.

 

[kigmatzomat]

You mention liking non-hp effects, perhaps movement would be a good one. Reduce their movement by 1ft per "new magic" item or maybe 5ft/attuned item or active "new" spell. Similarly, traps/constructs could either push or pull PCs based on their magic items/spells.

 

[M_Natas]

I like the Idea.

I would construct it a little different.

I would give the constructs charges to use their special abilities and depending on how hard you want it to be or what makes sense you can start with 0 charges or 1 charge or more ... and the ancient constructs regain charges by attacking the PCs and shutting down attunments.

Like ...

Mana Drain. Melee Spell Attack. +10 to hit, reach 10ft, one target. Hit 12 (2d6+5) force damage. If the target is a creature that is attuned to any magic item, the creature must succed a DC 14 wisdom saving throw or looses the attunment of one randomly determined magic item it is attuned to. If that happens the [Name of Magical Construct] gains one Manacharge. A magic item that got its attunement broken that way can't be reattuned until 24 hours has passed.

So the breaking of the attunment represents the Construct stealing the magical energy of the magic item to fuel its own powers.