You conjure a portal linking an unoccupied space you can see within range to a precise location on a different plane of existence. The portal is a circular opening, which you can make 5 to 20 feet in diameter. You can orient the portal in any direction you choose. The portal lasts for the duration, and the portal’s destination is visible through it.
The portal has a front and a back on each plane where it appears. Travel through the portal is possible only by moving through its front. Anything that does so is instantly transported to the other plane, appearing in the unoccupied space nearest to the portal.
Deities and other planar rulers can prevent portals created by this spell from opening in their presence or anywhere within their domains.
When you cast this spell, you can speak the name of a specific creature (a pseudonym, title, or nickname doesn’t work). If that creature is on a plane other than the one you are on, the portal opens next to the named creature and transports it to the nearest unoccupied space on your side of the portal. You gain no special power over the creature, and it is free to act as the DM deems appropriate. It might leave, attack you, or help you.
* - (a diamond worth 5,000+ GP)
Oh interesting, they changed GM to DM, other than that, very similar wording, I love it. I was always curious about that choice.
They should change it so you can't just force a creature into a trap using gate. Just make it open a portal next to the creature instead.
Why? It's a 9th-level spell, it should be scary.
It should be scary, not "I can kill a Demon Lord with it" scary. The real issue is that it wasn't intended to be a "I summon Malcanthet into a pool of lava" spell, it was intended to be a "you're allowed to go literally anywhere you want and take anyone and anything you want with you" spell.
Edit: I just realized that Demon Lords can say no to the spell, that said you could instantly kill any Pit Fiend or other powerful creature that you know the name of easily.
Can you not simply open a portal to the sun anyway and just blast whoever stands near the portal?
Ok, that's another problem. The best way to solve this would be to stop it from being made if anything other than air would naturally pour out of it (so not underwater or in the sun or anything like that). I'm sure someone could come up with a better wording than that but you get the idea.
Gate 1 opens vertically behind to the bad guy. Gate 2 opens 500ft in the air, facing downwards, into the negative energy plane. Have someone on the team shove/repelling blast/telekinesis the bad guy though the gate.
Bonus points if your DM allows this then immediately has a Nightwalker spwan though the gate.
The spell says you open a portal to "a precise location on another plane of existence", and that a thing must move through the portal. Of course, it's up to the DM to decide how a "precise location" is determined. To use a sun, the caster needs to know a precise location that is adjacent to a sun on another plane of existence, and the DM would have to rule that heat of the sun is a "thing" that is "moving" to come through the portal.
The Styx is a more reasonable choice, since the water is indeed moving and the river is on another plane. A caster could travel to the Styx on some Outer Plane, do whatever the DM decides is necessary to know a "precise location". That achieved, the caster can burn a 5000 gp diamond to create a 20-foot-wide stream from the Styx and deluge a whole bunch of people. The River Styx in the 2024 DMG is now defined as a "nuisance hazard" and is less intense than the deprecated feeblemind spell. As an attack, it's less effective than synaptic static. Could be interesting as a kind of curse on a caster. As an attack, a river of lava in some part of Avernus or the plane of elemental fire would make a lot more sense.
Of course, for the cost of a 9th level slot, you could just cast meteor swarm. In general, trying to use gate as an attack expecting a hazardous environment to come through would be far less effective and more expensive than would be worth it. Not only is it completely out of your control, but the DM could quite reasonably allow a save for creatures to avoid the effect, and the DC of the save is probably unrelated to the caster's spell save DC, but rather the DM's evaluation of the uncontrolled stream of material coming through.
Any DM worth their salt would rule that no fiend of any consequence uses their real name until they are powerful enough to simply ignore a gate. Learning a pit fiend's true name so that you can gate them into a trap and bind them would be a worthy part of an adventure, not an attack.
That whole "precise location" thing comes into play. Good luck to the caster on their expedition to determine a precise location in the Negative Plane, if the DM even rules it's possible. Even a relatively safe plane, like elemental air, needs some reference in order for a "precise location" to be specified, like "200 feet directly above the palace of Bob the djinni".