Can an Eldritch Knight use a Ruby of the War Mage?

As explained in How does an arcane focus work with an Eldritch Knight?, Eldritch Knights can’t use an arcane focus as a spellcasting focus.

Ruby of the War Mage (XGtE p. 138), however, states:

Etched with eldritch runes, this 1-inch-diameter ruby allows you to use a simple or martial weapon as a spellcasting focus for your spells. […]

This paragraph doesn’t mention anything about arcane foci or anything like that, but straight up says that you can use the weapon as a spellcasting focus; the only requirement being that you are a spellcaster (which is true for Eldritch Knights).

Can you use this magic item to circumvent the otherwise existent restriction to component pouches for Eldritch Knights? Or am I missing some rule that disallows this "trick" / workaround?

Can a rune knight give runes to allies?

It doesn’t disallow the rune knight from putting runes on ally’s equipment, or giving inscribed equipment to allies, but there’s also the difference of language from Artificer infusions, with infusions, it refers to "the wearer," and rune knight refers to "you." So it seems that it wouldn’t work.

Can a rune knight inscribe allies’ equipment and have them benefit from the runes?

Can an Eldritch Knight Attack Twice With Green Flame Blade and War Magic? [duplicate]

An 8th-level Eldritch Knight has a sword.

The War Magic class ability says:

When you use your action to cast a cantrip, you can make one weapon attack as a bonus action

And the cantrip Green Flame Blade says:

You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you

So I think that means there are 2 sword attacks in total for that turn.

One attack is a bonus action, and one is a side effect of the cantrip. In addition to that are the flame effects of the cantrip as well.

(The 2 attacks are not related to the Extra Attack Fighter class ability, which requires taking the Attack action, which is not being done here.)

Is the above information correct?

How does the altered Extra Attack feature of the Bladesinger (Tasha’s Cauldron version) interect with the Eldritch Knight Fighter’s War Magic feature?

The Extra Attack feature of the Bladesinger allows you to replace one of your weapon attacks with casting a cantrip. The Eldritch Knight’s War Magic feature checks if you have "use[d] your action to cast a cantrip." Technically, you have used your action to cast a cantrip, or at least part of your action. Can a Eldritch Knight 7 / Bladesinger Wizard 6 make a weapon attack and cast a cantrip with Bladesinger’s Extra Attack and then make a weapon attack as a bonus action with Eldritch Knight’s War Magic?

Is the Echo of a Echo Knight actually a creature?

I’ve always been certain that the echo created by an Echo Knight fighter using their 3rd-level feature Manifest Echo is not defined in game terms as a creature, since the description of the echo never explicitly tells it is a creature. But the presence of people believing the echo to be a creature in lieu of the fact that it is immune to all conditions and might make saving throws (game characteristics typically associated with creatures only) brought this doubt to my mind.

This tweet from Jeremy Crawford implies it is just an image and not a creature, further confirming that the feature should tell you, but this other tweet implies that the echo is an object whilst the feature doesn’t explicitly say so.
(Included for reference and insight, since tweets are not eligible as official ruling)

Is the echo a creature?

As a sword and board Eldritch Knight do I need to put away my sword on my turn if I want to use Shield as a reaction?

Without Warcaster, I can’t cast spells with somatic components if I have both a shield and a sword in my hands. Putting my sword away or dropping it is a free action, however you can’t do free actions outside your turn. So if I want to be able to cast Shield on myself as a reaction, do I need to always put my sword away at the end of my turn? (This also means I won’t be able to capitalize on opportunity of attacks).

When using the War Caster feat and an Echo Knight Fighter’s Manifest Echo where does the spell originate from?

Inspired by the following question:

  • Can an Echo Knight with the War Caster feat use cantrips for opportunity attacks made by their Echo?

The Echo Knight’s Manifest Echo feature states (emphasis mine):

[…] When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space. […]

And the War Caster feat states (emphasis mine):

[…] When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. […]

I am aware that the spell cast using War Caster does not count as an Opportunity Attack. And this makes me unsure what happens when a creature provokes an Opportunity Attack from the Echo and the Fighter chooses to use War Caster.

Is the spell cast from the Echo’s space because the Opportunity Attack would have been made from that space?
Is the spell cast from the Fighter’s space because the Maifest Echo feature only allows Opportunity Attacks to be made from the Echo’s space and not spells?
Is something else the case?

Can an Echo Knight with the War Caster feat use cantrips for opportunity attacks made by their Echo?

The Echo Knight has the following ability:

When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space.

The Warcaster feat has the following benefit (emphasis mine):

When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack.

If an Echo Knight has the War Caster feat and knows a cantrip like, say, Booming Blade, can they use the cantrip for opportunity attacks made from the position of the Echo?

Can an Arcane Trickster or Eldritch Knight who takes the Magic Initiate? [duplicate]

Can an Arcane Trickster or Eldritch Knight who takes the Magic Initiate (Wizard) feat cast the first level spell they pick with their spell slots, like a Bard who took Magic Initiate (Bard) can? Or the Wizard for that matter?

Both AT and EK uses the wizard spell list, so one could assume so, but can they?

This question have not been directly answered when it comes to Arcane Trickster or Eldritch Knight, so please do not close my question, the problem is if it counts for AT and EK.

I repeat, this specifik question needs to be clearly answered 🙂

Can an Arcane Trickster or Eldritch Knight who takes the Magic Initiate (Wizard) feat cast the first level spell they pick with their spell slots? [duplicate]

Can an Arcane Trickster or Eldritch Knight who takes the Magic Initiate (Wizard) feat cast the first level spell they pick with their spell slots, like a Bard who took Magic Initiate (Bard) can? Or the Wizard for that matter?

Both AT and EK uses the wizard spell list, so one could assume so, but can they?