Called creature extended stay

[Adjoint]

The spell lesser plany ally (and by extension, other spells that work like it) says that when the duration bargained for expires, the creature returns to its home plane. My question is: does it have to, if it doesn't want to?

To my understanding, some adventure plots start with a called demon or another such being getting independent and staying on the material plane to cause trouble.

[Pizza Lord]

Certain tasks which aren't necessarily open-ended, but could be stretched out or extended could allow a creature to stay. Most creatures wouldn't do this, but if one really wanted to stay they might be able to, based on the wording of the task.

Also, maybe in certain cases (typically planar binding rather than planar ally) a calling might go wrong and the creature could break free and basically run rampant.

[Bob Bob Bob]

Weirdly enough, with Planar Ally it looks like it has to go.

Planar Ally wrote:

At the end of its task, or when the duration bargained for expires, the creature returns to its home plane (after reporting back to you, if appropriate and possible).

There's no "may" or "might" or something like that. It says when the task or duration are done it goes home. It can report to you but it's not required.

By contrast, Planar Binding has a loophole that makes me think Devils designed it.

Planar Binding wrote:

Once the requested service is completed, the creature need only to inform you to be instantly sent back whence it came.

So if they never inform you the task is complete they can stay around forever. Similarly, if it breaks free of the trap it can attack or escape and nothing says it has to return.

So Planar Ally it has to go, Planar Binding there are ways for it to stay.

[Adjoint]

Bob Bob Bob wrote:

Planar Binding wrote:

Once the requested service is completed, the creature need only to inform you to be instantly sent back whence it came.

So if they never inform you the task is complete they can stay around forever. Similarly, if it breaks free of the trap it can attack or escape and nothing says it has to return.

So, if the summoner dies in the meantime, the called creature can't return home unless it finds some other way like plane shift? I feel like I can make a quest out of it...

[Pizza Lord]

Being the Rules section I can't say that that isn't correct. I'd would say that since there are 'safeguards' in place that make eternal, open-ended, suicidal, or otherwise permanent binding or calling difficult and problematic (for the spells being discussed), I would say that in the case of the caster dying the creature is free to go but they'd still need to complete their task (again, this is not written, but seems most likely). At that point they could leave, or stay as they wish and choose to leave if things go badly, like a group of adventurers finally catch up with them.

This allows for adventures and plot where a party could drive a demon away (off their plane) without necessarily having the power to banish it or dismiss it themselves by threatening its life sufficiently.