Larian Studios Forums Baldur's Gate III Baldur's Gate III - General Newbie Spell Questions

I am a longtime BG2 player and know nothing of ruleset 5e.

The spell Witch Bolt says "Inflicts Witch Bolt (2)" in the description. What is the (2)? Duration??

Why don't many spells show duration in their description?

Also some spells say requires concentration. What is this??
Does this mean the spell caster must stay still and do nothing else for the spell to continue?

I was a bit confused by that too, it shows up with other spells I can't recall which, but I think it might have to do with the fact that it creates another spell effect that you are able to trigger after casting it, in Witch Bolts case the ongoing damage you can deal after.

As for concentration, after third edition, there was an effort made to mitigate the amount of compounding spells a wizard go have going at the same time, 5e's way of dealing with this was to make certain spells require concentration to keep going. You'll recall in BG2 after a certain point, combats were just sequencer battles of attrition as every wizard put up three layers of protection magic in round one, theoretically now you'll only have to deal with one of those at a time.

Each spell can be cast at its own spell level or any higher spell level.
Some spells have a bigger effect if you cast them at a higher spell level.

I think Witch Bolt is a lv 1 spell that causes 1d12 damage.
If you cast it as lv2 spell it causes 2d12 damage.
At higher level usually damage spells cause more damage, healing spells cause more healing and you can give status effects to stronger enemies ( sleep, color spray )
Many spells do not have a different effect at higher levels, usually some buffs and debuffs.

Some spells require concentration.
You can use only use one concentration spell at a time. When you take damage you must make a constitution saving throw. The difficulty depends on the damage taken and if you fail your concentration and the spell effect ends.

Some spells allow you to do something every round or you can use the effect again. When you cast such a spell a new icon shows up that allows you to use the spell effect again.

Yes, the UI needs some updates. It a big mess at the moment, especially for spells.