Working on a GOO warlock/aberrant mind sorcerer

[Klorox]

These two classes fit together very well thematically, and it's a great multiclass combo (NO COFFEE SHENANIGANS FOR ME!).

I was planning on playing this character in an Out of the Abyss campaign, but the game fell apart. I think it works great, he would have been a victim of a mind flayer attack and went a bit mad while imprisoned and having his mind fed upon.

The question is how to build this character optimally. A friend of mine advised going to sorcerer 5 ASAP so I could fireball, but I was thinking perhaps warlock first, so I could get eldritch blast and agonizing blast going, making me always a factor in combat, and then adding sorcerer levels.

What's the best way to go?

Also, how many warlock levels are best for this type of character? I'd think only 2 or 3, but I'm not too sure. If I go 3 or higher, what pact fits this idea best?

Thank you!

[CheddarChampion]

Did you have a species in mind?

I suggest something like GOO 2/Aberrant X. Pick up Agonizing Blast and Hex, that'll have you set for damage.
If you really want 3 GOO levels, Pact of the Chain is good if you want an invisible scout, Pact of the Tome is good if you like utility cantrips or if you plan to pick up the Book of Ancient Secrets invocation.
V. Human is a good pick if you start as a Warlock. You can take Resilient (Constitution) as your level 1 feat and start with 8/16/14/10/10/16 for stats, or 8/13/16/10/12/16 if you want to pick up Moderately Armored later on. If you do choose V. Human, Devil's Sight is a useful invocation.

Quicken Spell can be good for double Eldritch Blast or for a Mind Sliver before Hold Person/Hypnotic Pattern/Slow etc. Someone on Reddit did a bunch of math that shows Heighten Spell is usually better for making your spells land, but since Quicken doubles as extra offense for you it's probably a better pick.
Subtle Spell is a great thematic matchup if you're leaning into the creepiness of such a character.

[RogueJK]

The above is good advice, but if you want to lean into the Psionics aspect, I'd start VHuman/CLineage taking Telekinetic instead. Starting with Sorcerer removes the need for Resilient CON.

Telekinetic is a CHA half feat, so you could start with an 18 CHA using Custom Lineage or a 17 CHA with Variant Human, plus also gives you something useful to do with your Bonus Action on turns when you're not using Quickened Spell.

So Sorcerer 1 with Telekinetic and 17/18 CHA, then GOOlock 2 for Agonizing Eldritch Blast and Devil's Sight (or something else useful like Repelling Blast), then all Sorcerer levels from there.

You have a Telekinetic, Telepathic, Double-Agonizing-Eldritch-Blasting, Cthulhu-serving Psychic Sorcerer.

(Note that Subtle Spell isn't as necessary on an Aberrant Mind Sorcerer, since you can already get that functionality on a number of your spells anyway through your Psionic Sorcery ability.)

[Bobthewizard]

Multiclassing sorcerer/warlock I'd either go sorcerer 5 or aim for sorcerer 3/ warlock 2 at level 5. You don't have to take agonizing blast before level 5 though. Until you get the second ray, it's not significantly better than just using a crossbow.

As far as GOO and aberrant mind, it's not the best multi class. They both get telepathy at level one so you don't get much out of combining them. While hexblade is overused, it really does work here much better. Just reflavor the weapon bond and hex as coming from your GOO.

Hexblade/ sorcerer is a pretty straightforward progression. Start hexblade 2, then go sorcerer all the way. I know everyone loves starting with CON saves, but I like having both CON and WIS so I'd rather start with wisdom and put the plus 1 into CON with resilient CON.

[ftafp]

These two classes fit together very well thematically, and it's a great multiclass combo (NO COFFEE SHENANIGANS FOR ME!).

I was planning on playing this character in an Out of the Abyss campaign, but the game fell apart. I think it works great, he would have been a victim of a mind flayer attack and went a bit mad while imprisoned and having his mind fed upon.

The question is how to build this character optimally. A friend of mine advised going to sorcerer 5 ASAP so I could fireball, but I was thinking perhaps warlock first, so I could get eldritch blast and agonizing blast going, making me always a factor in combat, and then adding sorcerer levels.

What's the best way to go?

Also, how many warlock levels are best for this type of character? I'd think only 2 or 3, but I'm not too sure. If I go 3 or higher, what pact fits this idea best?

Thank you!

Just a heads up, it might be better to go Fathomless over GOO. Goolock/aberrant mind gets almost nothing from the goolock subclass since the aberrant mind has the same spells and abilities at level 1, but fathomless lets you summon phantom tentacles from your nightmares which is a nice free bonus action to have on hand. If you do that, you might want to make your second invocation either repellling blast, grasp of hadar or lance of lethargy, each of which interacts beautifully with the tentacle's slowing effect

[Bobthewizard]

Just a heads up, it might be better to go Fathomless over GOO. Goolock/aberrant mind gets almost nothing from the goolock subclass since the aberrant mind has the same spells and abilities at level 1, but fathomless lets you summon phantom tentacles from your nightmares which is a nice free bonus action to have on hand. If you do that, you might want to make your second invocation either repellling blast, grasp of hadar or lance of lethargy, each of which interacts beautifully with the tentacle's slowing effect

I like this better than hexblade that I mentioned above. If you add repelling blast, lance of lethargy and gust of wind and then nothing can get to you while you plink away with your Eldritch Blast.