D&D 5E Oz, The Great and Powerful ( Trickery Cleric 2/Illusion Wizard 18/Feats ) - The Invincible Mage

Statistics

Name: Oz
Race: Deep Gnome
Class: Trickery Cleric 2/Illusion Wizard 18
Starting Ability Scores: 8 STR, 13 DEX, 15 CON, 17 INT, 13 WIS, 8 CHA
Level 20 Ability Scores: 8 STR, 13 DEX, 15 CON, 20 INT, 13 WIS, 8 CHA
Feats: Observant ( Intelligence ), Heavily Armored, War Caster, Spell Sniper
Spell Mastery: Shield, Misty Step

Powers

1-minute Invincibility: As been fully and elaborately discussed here, albeit too long to post in this thread, Oz can gain almost total invincibility for 1 minute while retaining his spellcasting capabilities for up to 1 minute and a range of 120 feet or more. ( Invoke Duplicity+Etherealness/Forcecage, Including True Seeing, Mind Blank and Heroe's Feast when needed )

Blessing of the Trickster: Oz can cancel the stealth disadvantage imposed by wearing heavy armor.

Armor Class: Oz can have a starting AC of 17 with Scale Mail and a Shield, 19 when sacrificing concentration for Shield of Faith, and up to 24 when using Shield. Oz's full non-magical potential with War Caster and Heavily Armored is an AC of 20 with Plate and Shield and 22 with Shield of Faith, up to 27 for 10 minutes with Shield and Spell Mastery. Magical potential with +3 Plate, +3 Shield, A ring/cloak/ioun stone of protection ( 2 ), and +2AC with the Staff of Power ( Ignoing Wand of Orcus +3AC ), you can have a permanent AC of 30 and 37 to 10 minutes with Shield and Spell Mastery, up to 42 with 3/4 cover. Heavy Armor without Strength will penalize your speed by 10 feet, but this class build doesn't really need speed, and it's cancelled with Longstrider for 1 hour anyway.

Superior Darkvision: Oz can see up to 120 feet with Darkvision

Gnome Cunning: Advantage on all Intelligence, Wisdom and Charisma saving throws against magic

Tiny Flight: Oz can initially or with enough diet weigh 80 pounds, and with Enlarge/Reduce for up to 1 minute with concentration, can carry his own weight with Mage Hand for up to 9 rounds ( 7 if recasting enlarge/reduce and Mage Hand ) to move up to 270 or 210 feet ( Doubled if recast, tripled if renewed 3 times, and so on ) flying, also passing through spaces as narrow as 1.5 feet. Useful for certain situations, or if one needs a very quick boost and just really doesn't want to spend a 3rd-level slot on Fly. Not useful for combat because moving the Mage Hand takes an action. At level 20 with Spell Mastery and choosing Enlarge/Reduce, Oz can have permanent flight this way ( Renewing Enlarge/Reduce at 8th round and Mage Hand at the 9th, moving for the rest ) in case various teleport slots have been expended or reserved and you want to reach somewhere in the air, in case for some reason you want to fly further than abilities such as Fly will let you, while reserving the spell slot ( Albeit with half the speed ), if flying mounts and creatures who need to rest every hour or two are insufficient, or unable to fly through certain aerial or planar terrain, or space ( While the Mage Hand never tires, takes no damage, isn't frightened, etc.. and your own size is 1.5 feet while weighing 10 pounds ), or if no flying magical items are available.

Spell Sniper: Choosing Eldritch Blast as a cantrip, With Invoke Duplicity, for 7 rounds ( Minus the 3 rounds it would take to move the Illusion up to 120 feet away from you ), Oz can cast spells as though he were in the Illusion's space, meaning a spell like Firebolt will now have a range of 240 feet from Oz himself when cast through the illusion, and with Spell Sniper, it's 360 feet. The same is true for all spells with an attack roll, to varying ranges.

Healing: Oz primarily uses the Cleric's spellcasting to heal himself with Cure Wounds or allies with Healing Word when needed ( Hence why the Wisdom modifier hardly matters ), and can even heal allies from afar with Cure Wounds using Invoke Duplicity, bonus action to move the illusion up to 30 feet, and an action to cast Cure Wounds through it.

Illusory Reality - Oz uses this to block off creatures from escaping with some kind of transparent box or sphere ( Such as those made of Diamonds ) with Major Image of 6th level or higher, combined with Silence for spellcasters, to block off a target from escaping and still affecting it with spells that require a line of sight. Foregoing Silence, the illusion of Invoke Duplicity can pass through the barrier to cast any other spell on the target, while the target can't affect it in turn. Foregoing both Invoke Duplicity and Silence, the Major Image can also be cast at 3rd level with concentration. Oz can also use it to create 3/4 or even total cover with Minor Illusion for himself.

You have a nice high-level trick that will help a great deal during a few combats a day at the cost of some very high level slots. Great when you're prepared for a huge combat, harder to judge when facing a number of combat.

Of course, it can backfire spectacularly if a foe teleports inside the cage with you, and at character level 15 when you are learnign you first 7th level wizard spells (delayed because of the 2 levels of cleric), I would expect that teleport, misty step, or the like is available to the foes in a decent percentage of combats. That said, even without the listed perfect selection of very rare and legendary items that would probably end up int he hands of a melee character first, you still have a good AC for your level and great INT save. (Yes, WIS and CHR do also have advantage, but without proficiency and especially with -1 CHR those saves are still more likely to fail agaisnt a save DC fo equal level to you at 15th or higher.)

Even without Forcecage, being able to hide around corners and cast is always good, though context dependent if it's worth the opportunity cost of your Concentration considering a high level spell list. It's only once per short rest, so you need to chose when to use it carefully - if you use it on a hard combat, you won't have ti for later combats until you get a short rest. For a wizard it's pretty easy to get a safe space to rest, but other factors may prevent taking an hour.

I think you miss counted your ASIs. A Clr 2/Wiz 18 will have 4 total. I count one raising your INT, and then 6 feats taken with your remaining three ... so you need to rework that some. If you don't take Observant you'll need another way to boost your INT.

Eldritch Blast, gained through Spell Sniper, will be based on you 8 CHR (last bullet point of the feat). With -1 to hit it's nigh useless.

Tiny Flight is a nifty idea. I'd allow it at my table. A more RAW DM will note that a mage hand has a very specific list of things it may do, and none of them allow it to manipulate a creature. You can get around this by having it grab a harness you are wearing, since "manipulate an object" is allowed. Careful, the total weight including gear needs to be 10 lbs or less after the 1/8thing of Enlarge/Reduce, but since the PHB says gnomes weigh 40-45 lbs this shouldn't be an obstacle.

While you can heal using higher level slots, it's not particularly efficient in the action economy. Healing Word would let you use a cantrip during your action, but with EB shown to have a really bad chance to hit I'm not sure any of the others are worth the time at the levels all of this comes together.

Your use of Illusionary Reality is spot on, but requires an illusion-creating spell of 1st level or higher. Are there any that don't require Concentration, since that would be incompatible with your main trick. If there is one without concentration you can also encase yourself in it when Forcecage is not available.

They can't teleport inside though, first of all depending on how Forcecage's "creating a solid barrier that prevents any matter from passing through it and blocking any spells cast into or out from the area." is interpreted . Most people I've talked to seem to interpret it as "Blocking any spells cast into the area, per se", so you can't cast teleportation or Misty Step into the area, but if you interpret it to mean "Can't cast spells through the physical Barrier only" or something like that, then it's also impossible either way:

Because I'm creating the Forcecage in box dimensions to fit me perfectly, and I occupy the space inside it. Neither spells nor even monster abilities let them teleport into an occupied space. It must be unoccupied space.

ASI's, you're right, it would only be 4 with Observant. I guess I'd have to take out Mage Slayer and Svirfneblin Magic. I suppose Eldritch Blast could be given up on in favor of Firebolt, it hardly matters really, as long as you have the Spell Sniper, since you're not using any invocations with it or whatever. Healing spells are just a good addition when you really need a heal. And yes, Major Image cast at 6th level or higher doesn't require concentration.

I will say though about Tiny Flight, according to the Elemental Evil Player's Companion, Deep Gnomes specifically weigh 80 pounds to 120 pounds. I think the Mage Hand's ability to carry anything ( Not just manipulate objects ) that weighs 10 pounds or less isn't a problem, but come to think of it, the weight itself would prove to be a problem since you'd need to carry nothing on you whatsoever, even an Arcane Focus would be too much, so I miscalculated a bit there too. I suppose now the question is - Would two Mage Hands ( no concentration, doesn't disappear when cast again ) grabbing me both by the scruff of my neck be able to carry up to 20 pounds, and I'd basically have to renew both ( And Enlarge/Reduce ) at the 4th, 5th, and 6th rounds before the 1 minute ( -3 to initially cast all 3, so remaining 7 rounds ), then rinse and repeat for permanent flight.

But regardless the Illusions do not necessarily have to be compatible with my main trick, they could act as a sort of a substitute ( I.E as 3/4 or total cover until destroyed ), but I guess once you're level 14 for Illusory Reality anyway, then you do have Major Image at 6th level or higher, lasting until dispelled and without concentration at all.

Renduaz said:

They can't teleport inside though, first of all depending on how Forcecage's "creating a solid barrier that prevents any matter from passing through it and blocking any spells cast into or out from the area." is interpreted .

Click to expand...

The Forcecage spell itself notes that it is permeable by teleportation, though it puts a limitation on trying to leave the box via it.

Renduaz said:

Because I'm creating the Forcecage in box dimensions to fit me perfectly, and I occupy the space inside it. Neither spells nor even monster abilities let them teleport into an occupied space. It must be unoccupied space.

Click to expand...

This, on the other hand, is more telling. Force cage dimensions are "up to" so you can create it for your size, and Misty Step requires an unoccupied space so it wouldn't work. Teleport however has no such limitation, so you could use it to teleport inside, you'd both just be squeezing.