dnd 5e – Can sequester be used to get nearly unlimited duration spell effects?

As a DM I would disallow a player from using this tactic. I think from a balance perspective, it would be game altering enough that it would create issues.

The game was built to generally only allow single concentration spells for one caster. And while there are a couple ways to break that, with things like storing a spell in a Shield Guardian (where the creature maintains the concentration after casting), Arcane Abeyance on the Chronurgy Wizard or Ring of Spell Storing where the activating character can maintain the spell (like a familiar), or storing spells in a Glyph of Warding (where the glyph is anchored in place and can’t move). It’s more difficult to do.

There’s potential interaction with the Glyphs of Warding & Demiplane where you could create a bunch of Glyphs holding the spells in a single location, where you open that location, buff up, and now have a lot of concentration spells active at once. But that still limits the spells to their normal duration, takes a lot of preparation, and is expended once you do it without a lot more prepartion.

This would break all of those restrictions.

If you were to do this, consider the possibility of how it could combine with something like Simulacrum & Demiplane. You could create a Simulacrum. Have it use it’s 7th level spell slot to cast another Simulacrum. Have it cast whatever buff you want that requires concentration. Sequester the Simulacrum. And then store that Simulacrum on a Demiplane. Rinse & repeat until you have all the buffs you want. The multi-simulacrum tactic itself is already one that I think most DMs would frown upon. But if you are going to allow never ending multiple concentration buffs, you’re already beyond that in terms of broken mechanics.

This tactic wouldn’t require the sacrifice of a player character for it. A singular Wizard could do it by themselves. That’s not really going to end well for a DM trying to run a balanced game.

There would be ways to deal with it. Dispel Magic could take care of it. And there are other ways to end spell effects. But then you are getting into a constant game of cat & mouse between you and that player.

Could it work? Depends on the nature of concentration. But I would recommend against it.