For a multiclassed caster targeted by Spell Thief, what spellcasting ability does the target use?

Spell Thief states:

[…] Immediately after a creature casts a spell that targets you or includes you in its area of effect, you can use your reaction to force the creature to make a saving throw with its spellcasting ability modifier. The DC equals your spell save DC. […]

For a multiclassed spellcaster who is the target of this feature, what spellcasting ability do they use to make the save?

For example, let’s say you have a Warlock 17/Wizard 3, targeted by this feature do they use Charisma or Intelligence for the check?

Does a “Thief Racket” Rogue gain an ability score boost to Dexterity at creation?

At character creation, the rogue class says under Key Ability : Dexterity or Other At 1st level, your class gives you an ability boost to Dexterity or an option from rogue’s racket.

Now, the thief racket allows such a rogue to use dexterity to deal damage with finesse weapons, and my interpretation was that such ability replaced the ability boost (which seemed balanced at first; a Thief would use Dexterity for hit/damage and AC after all, letting the character concentrate on a single ability score without being a caster). But recently I’ve seen the iconic rogue character sheet, and it seems that, as a thief rogue, the character’s Dexterity was 18+. So that’s it, is the iconic character sheet wrong? Or does the thief rogue keep the Dexterity ability boost?

Does the Thief rogue’s Use Magic Device feature let them ignore class, race, and level requirements on attuning to magic items?

The Artificer’s Magic Item Savant feature states (E:RftLW p. 58, WGtE p. 180; emphasis mine):

[…] You ignore all class, race, spell, and level requirements on attuning to or using magic items.

In contrast, the Thief rogue’s Use Magic Device feature merely states:

[…] You ignore all class, race, and level requirements on the use of magic items.

The Use Magic Device feature doesn’t mention ignoring requirements on attuning to magic items, only on using them. It seems like that would mean a Thief rogue can not attune to a magic item if it has a specific requirement on who can attune to it (e.g. the holy avenger).

Does the Use Magic Device feature let a Thief rogue ignore class, race, and level requirements on attuning to magic items?

Is To Catch a Thief based on an adventure (other than Dragon Heist)?

I have Escape the Underdark, and (as far as I can tell) it is based on Out of the Abyss. I also have To Catch a Thief, but it seems to share little with Waterdeep: Dragon Heist other than the setting. I saw A Tale of Two Fishies on Dungeon Masters Guild, but I don’t have it myself. Is To Catch a Thief actually based on this latter adventure?

Does the “use magic device” feature of the thief subclass allow you to attune to items requiring you to be a spellcaster?


Use Magic Device

By 13th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race and level requirements on the use of magic items.

This allows the rogue to attune to “sorcerer/wizard/warlock only” items. But is the restriction “requires attunement by a spellcaster” also covered by the trait?

The official “spellcaster restriction” is explained as follows:

If the prerequisite is to be a spellcaster, a creature qualifies if fit can cast at least one spell using its traits or features, not using magic items or the like.

The problem I have with that is, that I think RAW use magic device does not let you use an item restricted to “spellcasters”, but generally those items are supposed to be less restricted than other items which might be class exclusive. Did I overlook something?

Which originally published items does Use Magic Device from the Thief subclass cover?

This class feature seemed to me dead-on-arrival when published.

It’s unclear exactly what items originally presented in the DMG or PHB that this feature was originally intended to work with.

  • Exactly which items in the DMG or PHB are made usable by a level 13 Thief when granted the Use Magic Device class feature?

  • Of those items, which of them are meaningfully useful to a creature that doesn’t meet the requirements?

    (For example: Pearl of Power does nothing for a Thief even if they can ignore the class requirement of “spellcaster” so it is not meaningfully useful.)

Extending this question to all published works would be too vast of a question, but this should be a reasonable ask.

Could a Rogue [Thief] use a Wizard’s Spellbook to cast spells?

So I was wondering since the Rogue Thief has the ability Use Magic Device which states –

You have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of Magic Items

Would this ability overcome the class restrictions of a Wizard and allow a Thief Rogue to use it’s Spellbook?

Does an Artificer’s Magic Item Savant and a multiclassed Thief Rogue’s Use Magic Device allow them to benefit from a Rod of the Pact Keeper?

The Artificer’s Magic Item Savant feature states the following:

At 14th level, your skill with magic items deepens more:
• You can attune to up to five magic items at once.
• You ignore all class, race, spell, and level requirements on attuning to or using a magic item.

The Thief Rogue’s Use Magic Device feature states the following:

By 13th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.

Rod of the Pact Keeper states the following:

While holding this rod, you gain a +1 bonus to spell attack rolls and to the saving throw DCs of your warlock spells.

In addition, you can regain one warlock spell slot as an action while holding the rod. You can’t use this property again until you finish a long rest.

Since these features allow an Artificer or a multiclassed Thief Rogue to ignore “class” requirements when using a Rod of the Pact Keeper, would they ignore all instances of “Warlock” in the text and benefit from the general bonus to spell attack rolls and saving throw DCs, and be able to regain one spell slot?

Related questions:
1. What requirements does the Artificers Magic Item Savant feature ignore?
2. Does an Artificer's Magic Item Savant and a Thief Rogue's Use Magic Device allow them to benefit from a Holy Avenger's 30-foot aura?

Does an Artificer’s Magic Item Savant and a Thief Rogue’s Use Magic Device allow them to benefit from a Holy Avenger’s 30-foot aura?

The Artificer’s Magic Item Savant feature states the following:

At 14th level, your skill with magic items deepens more:
• You can attune to up to five magic items at once.
• You ignore all class, race, spell, and level requirements on attuning to or using a magic item.

The Thief Rogue’s Use Magic Device feature states the following:

By 13th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.

Holy Avenger states the following:

While you hold the drawn sword, it creates an aura in a 10-foot radius around you. You and all creatures friendly to you in the aura have advantage on saving throws against spells and other magical effects. If you have 17 or more levels in the paladin class, the radius of the aura increases to 30 feet.

Since these features allow an Artificer or Thief Rogue to ignore “class” requirements when using the Holy Avenger, would they gain the benefit of the 30-foot aura?

Furthermore, since they also ignore “level” requirements when using the Holy Avenger, can they benefit from the 30-foot aura at 14th and 13th level, respectively?

Related questions:
1. What requirements does the Artificers Magic Item Savant feature ignore?
2.

Does a Thief rogue’s Fast Hands allow you to drink a potion as a bonus action?

A recent D&D Beyond article, Epic House Rules: Potion Toxicity and Quick Drinking, mentioned this houserule:

Variant: Quick Potion Drinking

You can use a bonus action, instead of an action, to drink a potion you’re holding.

I mentioned in a comment:

The only reason I wouldn’t use the Quick Potion Drinking rule is if there was a Rogue with the Thief archetype in the party, since it kinda short changes their Fast Hands class feature (the “take the Use an Object action” part).

My reasoning was that a Thief rogue might feel less special if everyone can do something that RAW only they would be able to do. For reference, here’s what Fast Hands says (PHB, p. 97):

Starting at 3rd level, you can use the bonus action granted by your Cunning Action to make a Dexterity (Sleight of Hand) check, use your thieves’ tools to disarm a trap or open a lock, or take the Use an Object action.

Then another user, JamieMcGuire47, replied to my comment with the following information:

@nathanES RAW, you cannot do this. If a magic item (magic is the keyword here, as it divides regular item interaction from magic item interaction) specifically requires the use of an action to activate its ability, the Use an Object action does not apply to it (including fast hands).

The DMG pg.139 discuses potions:

Potions are consumable magic items. Drinking a potion or administering it to another character requires an action.

The DMG p. 141 discusses activating magic items:

“If an item requires an action to activate, that action isn’t a function of the Use an Item action, so a feature such as the rogue’s Fast Hands can’t be used to activate the item.

This suggests that, RAW, Fast Hands does not allow you to drink, say, a potion of healing as a bonus action. If this is the case, I would have to reassess whether or not I would use that rule (since apparently, it doesn’t short change the Thief rogue after all).

JamieMcGuire47’s reasoning and evidence looks pretty solid to me, and the only consensus I’ve found on this site seem to agree (although it doesn’t really go into proving that assertion); see: What items can a Thief use as a bonus action with his Fast Hands?

Is JamieMcGuire47 correct? Can a Thief rogue not use Fast Hands to drink a potion for the reasons stated?