Is Alter Self strictly better than Disguise Self as at-will invocations?

Question

PHB Page 211, Alter Self

You assume a different form. When you cast the spell, choose one of the following options, the effects of which last for the duration of the spell. While the spell lasts, you can end one option as an action to gain the benefits of a different one.

Change Appearance. You transform your appearance. You decide what you look like, including your height, weight, facial features, sound of your voice, hair length, coloration, and distinguishing characteristics, if any. You can make yourself appear as a member of another race, though none of your statistics change. You also can’t appear as a creature of a different size than you, and your basic shape stays the same; if you're bipedal, you can’t use this spell to become quadrupedal, for instance. At any time for the duration of the spell, you can use your action to change your appearance in this way again.

PHB Page 233, Disguise Self

You make yourself—including your clothing, armor, weapons, and other belongings on your person—look different until the spell ends or until you use your action to dismiss it. You can seem 1 foot shorter or taller and can appear thin, fat, or in between. You can’t change your body type, so you must adopt a form that has the same basic arrangement of limbs. Otherwise, the extent of the illusion is up to you.

The changes wrought by this spell fail to hold up to physical inspection. For example, if you use this spell to add a hat to your outfit, objects pass through the hat, and anyone who touches it would feel nothing or would feel your head and hair. If you use this spell to appear thinner than you are, the hand of someone who reaches out to touch you would bump into you while it was seemingly still in mid-air.

To discern that you are disguised, a creature can use its action to inspect your appearance and must succeed on an Intelligence (Investigation) check against your spell save DC.

Can the 2nd-level Alter Self spell make the 1st-level Disguise Self spell obsolete, either by perfectly replicating the spell's effects or by providing wholly superior effects? Based on past editions of D&D I would guess yes, but after reading the descriptions of the spells from the PHB I can't quite tell.

Specifically, I'm asking this question because the Warlock gets two different invocations: one that allows at-will usage of Disguise Self (Mask of Many Faces), and one that allows at-will usage of Alter Self (Master of Myriad Forms). The Warlock can also trade old obsolete invocations for different ones during a level-up. Is it advantageous to trade the Disguise Self invocation for the Alter Self invocation? Is it optimal for a character specializing in Stealth/Disguise/Social abilities to have both?

Answer 1

Strictly better? No.

One of the major points of Disguise Self is that it can not only alter your appearance (via illusion), but your clothing and equipment as well.

It's important to note the inverse of this: Alter Self does not specify that it modifies your clothing or equipment. This means that, depending on how severe your alterations are, you may no longer fit into your armor and your clothing may clearly no longer fit you, depending on how simulationist your DM is on the topic. This is especially important if using the "Variant: Equipment Sizes" rule on PHB p.144:

In most campaigns, you can use or wear any equipment that you find on your adventures, within the bounds of common sense. For example, a burly half-orc won’t fit in a halfling’s leather armor, and a gnome would be swallowed up in a cloud giant’s elegant robe.

The DM can impose more realism. For example, a suit of plate armor made for one human might not fit another one without significant alterations, and a guard’s uniform might be visibly ill-fitting when an adventurer tries to wear it as a disguise.

Using this variant, when adventurers find armor, clothing, and similar items that are made to be worn, they might need to visit an armorsmith, tailor, leatherworker, or similar expert to make the item wearable. The cost for such work varies from 10 to 40 percent of the market price of the item. The DM can either roll 1d4 × 10 or determine the increase in cost based on the extent of the alterations required.

Even if your equipment does fit you after the effects of the spell, any well known gear or accessories may still let you be identified, especially if they're more well known then your actual physical attributes.

There are a few other considerations as well.

One of them is that both Alter Self and Disguise Self can be used at the same time, to enhance the illusion with actual physical changes underneath it. Do note that this is only possible because Disguise Self does not require concentration, which is another point in its favor over Alter Self, which does. This means Alter Self can fail earlier than intended (especially in combat or while under stress), while Disguise Self will last the duration under most conditions, and still allows you to cast other concentration spells.

Another is comparing how Disguise Self and Alter Self interact with height & size.

Alter Self actually changes your height, while Disguise Self only creates the illusion of a height change, keeping you your usual size. This might matter if your DM actually cares about character height in certain situations rather than just your size.

In addition, Alter Self restricts you to only changing your appearance to a creature of the same size with no other restriction on maximum height gain/loss, while Disguise Self only has a restriction on height change rather than size change.

For example, with Alter Self, you could change the shortest possible dwarf into the tallest possible goliath, whereas with Disguise Self, you could make a dwarf appear to be a halfling (so long as you're not trying to change your height by more than a foot in doing so).

Overall, I'd probably rate Alter Self better than Disguise Self in some combination of the following situations:

• There is plenty of time to make preparations in advance, including having an appropriate alternate outfit ready.
• You are unprepared, but you only need minor superficial changes with no drastic change such as size, making the lack of alternate costume not an issue.
• You are in no danger of having your concentration broken for the next hour, nor are you likely to need to cast any other Concentration spells.
• You are likely to be thoroughly inspected for some reason or another.

In other situations, there is a chance Disguise Self may be the more appropriate spell. In a situation requiring an emergency drastic appearance change (clothes, size, and all), for example, I would much prefer Disguise Self as my option.

Answer 2

There are three main differences between Alter Self and Disguise Self, and No, Alter self is not Always Better. It's not even necessarily superior.

• First and most important difference. Alter Self is a concentration spell that lasts up to an hour, Disguise self lasts for 1 hour without concentration. This means that while casting alter self, you can not cast other concentration spells such as Invisibility or Fly. If you are on a stealth mission, you might need to make use of other concentration spells. As a warlock this means you can't use Ascendant Step (Which gives levitation) and Master of Myriad Forms at the same time. So depending on if you have other Invocations that also require concentration you might want to keep Mask of Many Faces (disguise self) and not take Master of Myriad Forms

• The second difference is that Alter Self is a transmutation spell and Disguise Self is an Illusion spell. This means that Disguise Self can be detected with an int check, while Alter Self can only be detected with a True seeing ability. Other differences may come up that key off these different schools as well, though I have not noticed anything that gives special attention to transmutaion that would ever make Disguise Self better for these differences.

• The third difference is that Alter Self only transforms your body while Disguise Self can also change your clothing. Sometimes, making yourself look like a different person who still has the same standard of living may not be as effective as changing your clothing and face to look like a pauper or noble. These are situational differences and sometimes Alter Self is good enough. (Especially if you know there are those who can easily spot illusions)

• Lastly, there is no reason not to use both spells at once for a double bluff, or if it's really important that everyone thinks you are a dwarf even after the illusion of different clothing and race fails. Since Disguise Self is not a concentration spell, you can cast it at the same time as Alter Self and have both active at once.

To reiterate. Because Alter Self is a concentration spell, this reduces it's "better" quality, since it greatly restricts other spells you might need to have going on for you. Because Disguise Self is only an illusion and can be detected, it reduces it's "better" quality. Disguise Self is useful for changing clothing and appearances and for doing other magic at the same time, while Alter Self is useful for when people will be physically interacting with you, and there is a chance that someone will detect the illusion. Using both together allows for the most secure "false identity".

Answer 3

I would say the ability to create the illusion of clothing, armour, weapons and other belongings is a very good reason to keep disguise self around.

Uniforms and rank designations can gain you access to things that changing hair color won't. If you wear the livery of the local guards, you will almost certainly be accepted as a guard and permitted into the barracks.

In combat, appearing to be wearing plate and holding a shield might convince your opponents to attack someone else, or to not attack at all. This of course comes down to how your DM plays NPCs, but generally, moderately intelligent monsters understand that attacking people without armour is likely to produce better results.

If you're disarmed and in a prison, create a makeshift sling ( a strip of cloth) and disguise self to appear as yourself with a loaded crossbow. When the gaoler comes by to feed you, it's then a simple bluff of "release me or I'll shoot you".

Alternative get out of gaol card? Disguise self as the gaoler from the night shift who is tied and gagged. When the day shift gaoler opens the door to free you, they will quickly find you are not actually tied up and can cast spells.

Impersonating an individual person will raise suspicion if you do not also impersonate clothing/gear they usually wear/carry.

The advantages of Alter self include being able to change your appearance multiple times and that the changes stand up to bodily contact.

There could easily be advantages of combining both spells.

A scenario in which the spells could be combined quite simply.

You want to impersonate the local lord, who is short and bears a shield with his family crest on as well as a sword with a distinctive design.

With Disguise self, you can hold an ordinary shield and sword, and use disguise self to make yourself look short, and make your weapon and shield mimic the distinctive items. However, you will need to duck when passing through low doorways, which will look odd for a short person to be doing.

With an alter self, you could transform into the lord, but would have to pantomime some indignation and start a manhunt to find the guy who mugged you and stole your items. This will draw an undesired level of scrutiny.

With both, you are able to take on the complete appearance and form of the lord and his items and decrease your chances of being discovered.

Answer 4

To answer the title question:

Yes.

Alter Self is a much more powerful disguise effect, allowing you to reconfigure your disguise as often as needed during the duration and not allowing an automatic save when you get interacted with physically because your transformation is real, not an illusion. Your body actually physically changes to match your desired disguise, which overcomes many of Disguise Self's weaknesses.

Except...

The questions you ask in the body of the question are a bit different. If a heavily Stealth-focused character were to have at-will access to both spells, would he have additional benefits above and beyond the powerful Alter Self spell? Yes, significant benefits, actually.

• A psychological benefit - Should your Disguise Self spell be overcome, and someone discovers your "true" appearance beneath it, they are very likely to assume that really is your true appearance and not dig further. Your Alter Self layered beneath the illusory Disguise Self can trick someone into thinking they've found you out, when they're still not even close.

• A convenience benefit - Because Disguise Self masks what you look like beneath the illusion, you can use Alter Self's ability to change your appearance right there in broad daylight with no one the wiser. For example: The character is human. While hidden, he casts Alter Self to look like an elf, but layers Disguise Self over that to appear half-orcish. Then, as he approaches the person he plans to "reveal his true self" to (in order to gain their confidence), he realizes that his information was wrong - the person is Eladrin, not Elf! Were he using only Alter Self, observant onlookers might notice if he suddenly changed from being an elf to an eladrin; but this warlock has no fear of being discovered, since all the onlookers see only his half-orc appearance anyway. He adjusts the necessary details - hidden in plain sight - and then when he later drops his disguise to the eladrin, his second disguise is perfect.

• A communication benefit - This one is iffy in 5e, and probably falls into house-rule territory, but I'm including it here in case your party has access to magics that let you pull it off with rules-as-written or else you have a DM that's willing to allow it. In many roleplaying games, someone who realizes the truth under an illusion actually gains the ability to see through it - they see the illusion super-imposed over the reality. In other cases, some magics automatically defeat the illusion and reveal the truth beneath. Typically, neither of these cases overcome Alter Self (short of True Seeing, anyway), as I mentioned in the first paragraph. Clever parties have used this effect to permit near-undetectable coded distance communication: Set up ahead of time a code so that your assumption of particular shapes have particular meanings. "Blonde female elf" could be "create a distraction", while "bald male dwarf with braided beard" might be "I have been made, prepare for combat". Set up your Disguise Self spell, appropriate to the situation, and then let your party members physically interact with (and thus defeat) the illusion (or just have them cast their spell that lets them see through it). Now, while the rest of the world still sees your illusory Disguise, your party can see your coded messages underneath as you change forms to transmit information.

These are probably only the start... would I say a character who keeps both is "optimized"? Probably not. Does it sound fun as heck to play? Yes, indeed. A creative player can build on or just be inspired by these benefits and find more and more ways to combine the two spells to endless effects.

Scott's answer points a key benefit that I forgot to mention, so all credit for this paragraph is his: Disguise Self can specifically change your clothing and equipment's appearance as well, while Alter Self cannot. By layering a false image over the real thing, you can display anything you want with Disguise Self, while Alter Self specifically only changes your body. This effect can be exploited to completely confuse or get the drop on enemies. Display a holy symbol and make your dagger look like a mace, and foes will think you're a cleric. Give yourself a bow and twin short swords on your belt, and people's mind jump instantly to ranger. If nothing else, a spell component pouch and some robes could at least make them think you have a limit to your spells-per-day...

Answer 5

They have different pros and cons, including a benefit to Alter Self not yet addressed

I'm coming in almost a decade late to this question, but there's one detail overlooked in all the other answers that I think some DMs (myself included) would pay attention to: Voice.

Alter Self says "You decide [... the] sound of your voice". Disguise Self does nothing to change your voice. So if you are an elderly male wizard who wants to pass himself off as a young woman, Disguise Self may be very effective at the visual aspect of the deception, but the moment you open your mouth, you're probably going to give yourself away (barring something like the Actor feat, or the Kenku mimicry trait, or similar). However, Alter Self will ensure that your gravelly grumpy old sage sounds are replaced by the quite different strains of youthful femininity. What Alter Self won't do, however, is turn your tobacco-stained wizarding robes into a ballgown suitable for meeting the prince.

And neither spell will remove the smell of garlic and anchovies from the pasta you ate for lunch and replace it with alluring perfume. For that, you might need to cover with a little Prestidigitation.