Can I get an ally out of grapple with Thunder Step?

Question

Provided the ally is the same size or smaller than me, is within 5 feet of me and that there is space for him at the space I teleport to could I Thunder Step him out of grapple?

Thunder Step:
You teleport yourself to an unoccupied space you can see within range. Immediately after you disappear, a thunderous boom sounds, and each creature within 10 feet of the space you left must make a Constitution saving throw, taking 3d10 thunder damage on a failed save, or half as much damage on a successful one. The thunder can be heard from up to 300 feet away.
You can bring along objects as long as their weight doesn’t exceed what you can carry. You can also teleport one willing creature of your size or smaller who is carrying gear up to its carrying capacity. The creature must be within 5 feet of you when you cast this spell, and there must be an unoccupied space within 5 feet of your destination space for the creature to appear in; otherwise, the creature is left behind.

Answer 1

Yes this will work

The Grappled condition states:

[...] The condition also ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the thunderwave spell.

There are already quite a few questions on different methods of escaping a grapple including (but not limited to):

• Can you shove your way out of a grapple?
• Does shoving a creature break its grapple on another?
• Can you grapple-drag someone out of a grapple?
• What are the options for my restrained and overwhelmed spellcaster NPC?

All of these work as ways to get a creature out a grapple because they remove the grappled creature from the reach of the grappler. The last one in particular mentions misty step as a means of escaping a grapple which shows that teleportation is a valid means of escape. Now looking at the thunder step spell, we see that it states:

[...] You can also teleport one willing creature of your size or smaller who is carrying gear up to its carrying capacity. The creature must be within 5 feet of you when you cast this spell, and there must be an unoccupied space within 5 feet of your destination space for the creature to appear in; otherwise, the creature is left behind.

No part of this says that the creature must not be grappled or provides any restrictions that would prevent a grappled creature from being teleported. Thus, a grappled creature is a valid target. Additionally, nothing in the grappled condition prevents the creature from being moved by something like thunder step, similar to how misty step would work, so this too will work.

Answer 2

Yes.

The text of the Grapple description says:

A grappled creature’s speed becomes 0, and it can’t benefit from any bonus to its speed.

The condition ends if the Grappler is incapacitated (see the condition).

The condition also ends if an effect removes the grappled creature from the reach of the Grappler or Grappling effect, such as when a creature is hurled away by the Thunderwave spell.

As you can see, thunderstep would remove the grappled creature/player from the grasp of the grappler.

Thunderstep is even better then the Thunderwave used in the description as you are disappearing from the space you were in, instead of getting pushed.

Answer 3

Yes, it will work.

The thunderstep spell will allow you to get your ally out of a grapple as long as they are within 5 feet from you. this is because the thunder step spell says near the end:

You can bring along objects as long as their weight doesn’t exceed what you can carry. You can also teleport one willing creature of your size or smaller who is carrying gear up to its carrying capacity. The creature must be within 5 feet of you when you cast this spell, and there must be an unoccupied space within 5 feet of your destination space for the creature to appear in; otherwise, the creature is left behind.

this may be a better option than teleport if you and your ally are closer together because the thunder step spell says:

each creature within 10 feet of the space you left must make a Constitution saving throw, taking 3d10 thunder damage on a failed save, or half as much damage on a successful one.

and

the damage increases by 1d10 for each slot level above 3rd