Can a Titanosaurus summoned with the Conjure Fey spell use its legendary actions?

Question

The Monster Manual has a strong restriction on legendary actions with regard to creatures merely assuming the form of a legendary creature:

If a creature assumes the form of a legendary creature, such as through a spell, it doesn’t gain that form’s legendary actions, lair actions, or regional effects.

The Conjure Fey spell can summon a fey that takes the form of a beast:

You summon a fey creature of challenge rating 6 or lower, or a fey spirit that takes the form of a beast of challenge rating 6 or lower.

Since a fey spirit is taking the form of a beast, does this mean a Titanosaurus (from the AL-legal Beasts of the Jungle Rot product) summoned through Conjure Fey (with a level 7 slot) cannot use its legendary action?

Answer 1

It likely shouldn't, but this is an edge case because of the origin of the content

As you've quoted

If a creature assumes the form of a legendary creature, such as through a spell, it doesn’t gain that form’s legendary actions, lair actions, or regional effects.

should still apply to conjure fey because you are conjuring a fey via a spell that then assumes the form of a legendary creature

You summon a fey creature of challenge rating 6 or lower, or a fey spirit that takes the form of a beast of challenge rating 6 or lower.

Fey Creature vs Fey Spirit

I won't speculate on designer intent, but it is likely the options for Fey Creature vs Fey Spirit are functional to separate out your conjuring options:

1. Fey Creature lets you pick a creature of the Fey type of CR 6 or lower
2. Fey Spirit lets you pick a beast of CR 6 or lower

But functionally, a spirit is not different than a creature. Spirit isn't a creature type, but there are many 'spirit' creatures in the monster manual. Spirit may be a type of Fey, and a Fey is a creature.

A note on conjure spells

While most tables likely let the player pick what is conjured, that is not necessarily the way the designers intended.

A further note on the material

The AL legal supplement cited is not necessarily going to be available at every table. Each DM at each table can decide what content they allow and what they don't. Just because it exists doesn't mean it's an always-on option. That still is up to the DM.

While AL legal, this is not content produced by WoTC, and there are no WoTC Fey creatures that normally qualify that have legendary actions.

Having said that, my very brief look at the supplement does make it seem pretty cool :)

Answer 2

It should not get Legendary Actions

So, we have the line from the spell conjure fey:

You summon a fey creature of challenge rating 6 or lower, or a fey spirit that takes the form of a beast of challenge rating 6 or lower. It appears in an unoccupied space that you can see within range.

The part tripping you up is bolded. You are assuming that spirits are different from creatures but that isn't the case. Spirits are kind of creature. Even the explanation of monster/player sizes is under the heading "Creature Sizes". All monsters, NPCs or PCs are creatures (including fey which a fey spirit would be).

By Counter Example

We see that in the next line, it starts referring to both options as "the fey creature":

The fey creature is friendly to you and your companions for the duration.

If the fey spirit were not a creature, it wouldn't have to be friendly to you which would make the spell a much more interesting and much less useful spell. Find Familiar uses the same language "You gain the service of a familiar, a spirit that takes an animal form..." If they weren't creatures they couldn't be targeted by any spell that says "Target one creature within range..." or "All creatures in the area must make a ... saving throw..." Meaning they'd be invincible.

Answer 3

Yes it should gain Legendary Actions, but this definitely needs clarification

If a creature assumes the form of a legendary creature, such as through a spell, it doesn’t gain that form’s legendary actions, lair actions, or regional effects.

It seems that the original intention of the passage was to prevent players from using Spells such as Shapechange and True Polymorph to break encounters by abusing the action economy.

You summon a fey creature of challenge rating 6 or lower, or a fey spirit that takes the form of a beast of challenge rating 6 or lower.

Conjure Fey does make a clear distinction between a Fey Creature and a Fey Spirit, meaning that it isn't a creature assuming the form of a creature, but a spirit assuming the form of a creature. I would say that the ruling doesn't apply in this case, and it does gain the legendary actions.

However, the fact that a CR7 Beast with legendary actions exists is a pretty glaring balance issue in my opinion, and I wouldn't allow this to happen in my game regardless of the ruling.