Hi Dnd fans

I am playing as a sorcerer, but I am having suspicion that something is wrong.

Prologue, Assassins attack. But the only spell that somehow harms them is Magic missile.
Any other spell causes a cloud appear over their head

Do sorcerers use *only* charisma or I need more wisdom to make my spells work?

Or everything is ok and I need to level up before engaging superior foes

Thank you

gogwitcher300

Sorcerers only need charisma. However, most spells give the enemy a chance to resist them. The higher your charisma, the better the spell's chances of success (every 2 points of charisma is a +5% chance). Some low-level spells, such as sleep and color spray, can fail entirely against particularly strong foes. I don't think the assassins in the prologue are that powerful, but some of the enemy stats in the NWN1 OC are completely bonkers so maybe they are.

What other spells are you using?

Maybe your CHA is too low. Create the sorc with 18 to give yourself the best chance to land spells that allow saves. The OC only gives you 4 levels to increase CHA (max Level 18 toon) so the higher the better.

Those are only Level 3 wizards in the ambush but they are probably winning their saves against spells. Magic Missile doesn't allow a save so it will always hit unless there is some SR to thwart it but, in this case, SR is not a factor. If you keep reloading/replaying the same battle over and over, you should see your other spells begin to land just by sheer probability... unless you are the unluckiest player on the planet.

Keep leveling and adding CHA each opportunity to increase your spells per days and spell DC.

Only one stat directly affects spell casting, for sorcerers it is charisma. Yes, you need at least 19 to be able to cast all spells (by the time you get level 9 spells), but try to boost it higher. Not only does it make your spells harder to save against but you get more spells per day. See table on p72 of the manual.

Wis is the least useful stat for a sorcerer: it only affects will and some skills. Dex bonus gets added to AC, which is useful to an arcane caster with limited armor options. AC keeps you from getting hit and thus breaking concentration. Other than that neither stat affects casting.

You can increase one attribute of your choice at the 4th level and every 4 levels thereafter. Items do not allow you to access higher level spells (note: this isn't true of pen and paper D&D, where magical items can be used to meet spellcasting requirements and feat prerequisites). Some spells do not hit automatically and require you to make an attack roll. Dexterity helps with those spells. Wisdom has no effect on Sorcerer spellcasting and is tied with Strength as your least important attribute.

Funny you should mention pally because it is the natural synergy class for sorc. A single level of paladin
will vastly improve your saves and allow your toon to equip martial weapons. 2 levels will make you immune to fear which you are already aware.

However, assuming you can reach the maximum level 18 in the OC it would prevent access to level 9 spells which require at least 18 levels of sorc. But using a henchman, summon and familiar in encounters will reduce your combat experience drastically, somewhere around 10-12% per ally, so the prospect of reaching level 18 is a dubious expectation at best.

WIS is used for Will saves which a sorc already has as its high save. Not needed much. Use empowered Owl's Wisdom,
if needed for an extra boost vs. mind effects like fear.
CON is used for Fort saves,one of the typical weaknesses for mages, and HP total. Probably #2 priority just behind CHA.
DEX is used for reflex saves and AC but it (the AC) can be lost under certain circumstances. There are defensive feats like Dodge that require more DEX than is customary for a mage to allocate. Some mages like a bit of DEX to make their xbow better. Buffing with empowered Cat's Grace will raise the AB up to +3 in those cases.
INT will boost your Spellcraft, being able to recognize enemy spells and increase skill total.
STR is about worthless for a mage unless playing a spellsword of some kind. Most will use a polymorph like Tenser to melee, if needed. Empowered Bull's Strength can raise STR up to +7 when you need that extra boost.
CHA you already know about, the #1 priority for sorc.

As a player new to the game, check the NWNWiki (if you haven't already) to help you learn the basics, the advanced concepts and everything in between.

For some reason, those mages have 12 Spell Resistance. This means they have a chance to resist your spells outright, which is sometimes occurring. For most level 1 characters this chance will be 50% for SR 12.

You'll want to start with at least 16 Charisma and increase it every 4 levels...but Charisma does not help you overcome Spell Resistance. Only (Greater) Spell Penetration (feat), Greater/Lesser Spell breach (spells), or being higher level will do that.

Yep, that appears to be my problem.
I have 18 Charisma but,
I've wasted many points into wisdom.

I'll just restart my play through with a better character.

An as I understood correctly , Wisdom is only for *Wizards*?

Wisdom is mainly for Clerics, Druids, Paladins, and Rangers. That said, it still gives a higher Will save. What are your current stats, you're probably fine.

www.d20srd.org is also useful at times, although NWN does not strictly comply to 3.5 rules (it predates them and also differed from 3.0 in some details).