Larian Studios Forums Baldur's Gate III Baldur's Gate III - Build Discussion Spell Spammer

The basic idea is: Get one extra bonus action and use Sorcerer Quickened Spell to throw out 3 (or 4 or even 5) spells/cantrips a round. It burns through spell slots very quickly but the burst damage is vicious.

Get your extra bonus action from Rogue Thief (level 3) or from Pyroquickness Hat or the Helmet of Grit. Practically, the headgear are not available until Act 3, so you want to go with Rogue.

The basic build is Rogue (Thief) 3, Sorcerer 9. Build the stats like a Sorcerer: Charisma primary. Always take Haste as a Sorcerer spell and Quickened Spell as one of the metamagics. If you want to be able to throw out AoE attacks without trashing your allies, it is Rogue (Thief) 3, Wizard 2 (Evoker), Sorcerer 7, and use the memorized Wizard spells for defenses like Shield and Absorb Elements which don't use spell DC to attack.

The build never achieves 6th level spells and the Evoker option never achieves Sorcerer 5th level spells, so your best bet is to specialize in something that can do more damage. Draconic Bloodline (Red or Gold), plus the feat Elemental Adept: Fire is a good combo.

The basic combat strategy is to use Haste (or Potion of Speed or Haste Spore Grenade) at the beginning of combat and then pump out spells (or cantrips) for every Action and Bonus Action you have every round until you burn through your spells slots. If you run out of Sorcery Points before running out of spell slots, restore them using the standard Sorcerer abilities.

There are many, many ways to get more spell slots or otherwise extend your resources:
Tactics: You can extend the working life of the spell spamming by casting cantrips with the Actions and saving the Bonus Actions for the quickened higher level spells.
Wizard: Arcane Recovery (out of combat)
Astral Tadpole: Freecast. This also saves the Sorcery Points if used on a quickened spell.
Astral Tadpole: Mind Sanctuary. No longer have to use Quicken Spells while it lasts - saves tons of Sorcery Points.
Equipment: Staff of Spellpower or Markoheshkir allow one free cast. This also saves the Sorcery Points if used on a quickened spell.
Equipment: Pearl of Power Amulet or Spell Savant Amulet allow for spell slot recovery.
Elixirs: The Elixirs of Arcane Cultivation (in any of 4 variants) give a filled spell slot. Taking the exact same one again does nothing, but you can take a different level (regular, Greater, Superior, or Supreme) and keep getting extra spell slots for as long as you have elixirs and the Bonus Action to take them.

While it would be absolutely lovely to use the Staff of Cherished Necromancy to offset some of the costs, sadly, it doesn't work out well because the best necromantic spells are 6th level and the build never gets above 5th level spells.

I have a variant that is a sniper cantrip spammer.

Class: At least 3 levels of rogue to get the thief subclass. Take a fourth level if you want another feat and invest the rest in sorcerer. You could go for two levels of fighter at the expense of some spell slots for action surge to really alpha strike in the first turn.
Feats: Spell Sniper and Alert, I went for a third feat of Ability Improvement to boost my spellcasting attack modifier. Elemental Adept can be a good option too.
Equipment: All gear that lowers the threshold for criticals or gives free crits.
If you go with tadpole powers, Luck of the far realms for a free crit, Mind Sanctuary for free quickened spells without using sorcery points and Freecast for saving more sorcery points,
Spells: Does not matter, you use all spell slots as sorcery points for your quickened cantrips. Perhaps keeping some slots for a Counterspell sometimes. You can go for Haste, but I generally avoid it because it is so easy to lose concentration and lose an entire turn due to lethargy. Prefer potions of speed if I need some haste and very few battles will last longer than the potion effect when you go all in with haste.
Elixirs: Vicousness if you want to do more crits for taking down big bosses faster, Bloodlust for extra attacks if you are dealing with mobs, Arcane Cultivation if you want your sorcery points to last longer.

What does it do:
Without Haste using simple Fire Bolt and twinned spell and quickened spell you shoot four fire bolts at 3d10 damage per turn (three at the same target). Due to the increase in crit chance one or two of those should crit every turn equaling 15-18d10 of damage, 83-99 damage per turn, using only cantrips and sorcery points. For versatility against enemies with resistances, have the other cantrips available as well and choose Eldritch Blast as your back-up spell with the Spell Sniper feat since almost no enemies have resistance to force damage.
When you really want to maximise the damage output, you don the Gemini Gloves, use Haste, toss some water on the enemy and go for Cold Ray instead. Giving you seven cold rays (five at the same target) for 6d8 damage each. Three of those should crit on average for a total of 60d8 damage, 270 damage on the turn (out of which 189 points of damage can be delivered to the same enemy) and 216 damage per turn on subsequent turns because you cannot use the Gemini Gloves anymore. By the time a potion of speed has run out you should have done some 700 damage to the battlefield (and burned through 24 sorcery points, make sure to convert spell slots into sorcery points before the battle so you don't need to waste bonus actions during the fight). This is just with cantrips, If you keep some higher level spell slot open and toss in some bigger spells the potential damage output is larger. But the build relies on spells that use attack rolls since they can score critical hits and by the time you reach level 10, few spells with attack rolls actually do a lot more damage than cantrips and the spell slots are needed as sorcery points to fuel your quickened spells.
This assumes that you are able to find a position of high ground and some rolls with advantage like attacking out of stealth, using Tides of Chaos etc meaning that your attacks should almost never miss. Generally if your chance to hit is lower than 80% it is probably worthwhile to use a bonus action to hide and get advantage on the next attack for a much greater chance to hit and score a critical.
Very few enemies can resist this spell spammer as you can usually find at least one damage source that they aren't resistant to and there are no save rolls or anything else to resist the damage from cantrips (toss in a chill touch if they have the annoying habit of healing themselves) and if they want to use their reactions and counterspells to counter cantrips they will run out of spell slots and reactions a lot faster than you spam them.