Larian Studios Forums Baldur's Gate III Baldur's Gate III - General system question : which ability is linked to a given spell ?

It's mostly by class.

Wizards will use Intelligence for all their spell attacks and save DCs.
Warlocks will use Charisma (as will Paladins, Bards, and Sorcerers when they come)
Clerics, Druids, and Rangers use Wisdom
Arcane Tricksters and Eldritch Knights use Intelligence as they are fluff-wise treated as mini-wizards.

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The spell you are speaking of has two elements:

First you have to hit with a Weapon attack which will use either Strength or Dexterity depending on the weapon (Dex for bows). They will then roll against your spell save DC based on your Wisdom because Ranger.

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There are basically two ways aggressive spells operate.

Spell Attacks - the caster rolls an attack as if it were a weapon

Spell Save - the target rolls a Saving Throw determined by the spell (Strength for Ensnaring Strike) vs a DC determined by the caster's casting trait.

Some spells do use a mix... succeed in an attack to hit the target and then the target makes a save to resist some of the effect.

The spell save DC is 8 + Proficiency Bonus + Spellcasting ability score's modifier

A ranger of 1st to 4th level with 16 Dex and 14 Wis will have a bow attack of +5 (+7 if archery fighting style) due Proficiency bonus of +2 and Dex bonus +3. And Save DC of 12 because - 8 +2 (proficiency) +2 (Wisdom modifier)


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So process in this case is:

Cast spell

Make bow attack with +7 (we'll assume Archery style) and try to match the target's Armor Class.

If misses, the spell lingers because it triggers only on the next hit within the minute duration.

If the attack hits, the spell triggers. The target now must make a Strength saving throw to beat the above ranger's save DC of 12.

If the save fails, the target is affected by the spell. If the save succeeds, the spell fizzles.

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With half-casters whose spell-casting stat is usually secondary, I usually suggest spells that are more along the lines of buffs to self (Jump, Expeditious Retreat, Mirror Image, etc) or others since it means you aren't as heavily impacted by the spellcasting stat's level.