Custom spells/Character options?

[Asmotherion]

Is there a guid to make balanced custom spells? Any guidlines?

For example, let's imagine I want to a lava pit AOE (sphere/transmuting the ground) that does 10D6 fire dmg and gives a dexterity saving throw. It obviously makes the ground difficult terain, and due to the range, it's probably a con save throw. What level should it be?

How would it differ from a spell that is a lava cone raining lava down (apart that it could be a dex saving throw) in putting it to the right level?

Now, let's say I want to make the same spell have an option at becoming permanent if you maintain concentration. Would that scale it far above it's counterpart?

Also, one player asked me if he could take telekinesis at will as an invocation. He argued that there is always the ring of telekinesis, and that it could function as one. It can fit for a level 15 prereq. Invocation. However I'm not sure what other spells might quallyfy. I am thinking about baning the Idea, as he could very well find sayed ring, but he says he just wants it for flavoring of his character. Not sure how to react here.

[Citan]

Is there a guid to make balanced custom spells? Any guidlines?

For example, let's imagine I want to a lava pit AOE (sphere/transmuting the ground) that does 10D6 fire dmg and gives a dexterity saving throw. It obviously makes the ground difficult terain, and due to the range, it's probably a con save throw. What level should it be?

How would it differ from a spell that is a lava cone raining lava down (apart that it could be a dex saving throw) in putting it to the right level?

Now, let's say I want to make the same spell have an option at becoming permanent if you maintain concentration. Would that scale it far above it's counterpart?

Also, one player asked me if he could take telekinesis at will as an invocation. He argued that there is always the ring of telekinesis, and that it could function as one. It can fit for a level 15 prereq. Invocation. However I'm not sure what other spells might quallyfy. I am thinking about baning the Idea, as he could very well find sayed ring, but he says he just wants it for flavoring of his character. Not sure how to react here.
Hi!

There is little advice in the DMG, mainly about what scale of damage should be followed. In short, from 2d10 to 13d10 for a single-target spell, from 2d6 to 13d6 for multiple targets.
(Which I see a bit strange personally, considering that multiple target can be from 2 to easily 5 depending on the range and shape, but wel...)

To give you my personal opinion on your examples, although I'd say it also depends very much on the range...

1. Don't understand well your idea of duration, is it instantaneous (but if so, why would terrain become difficult)?
Let's say that you were talking of a spell with a 10-feet radius, instantaneous. I'd make this probably a 4th level spell at least, mainly taking Fireball as a base of comparison: shorter radius but higher damage and additional effect.

But it's the "difficult terrain" effect a bit sad, because small. So if you were envisioning rather a large area, such as 30 feet radius, then it would be at least lvl 6, because potentially many more creatures hit.

2. No opinion on this actually, sorry.

3. Again, it depends on many things. If you make the spell have a heavy cost (such as a rare ingredient that is consumed if you make the spell permanent) and/or requiring a very long cast (similar to Plant Growth), I would find it be acceptable to keep it only one level higher.

4. Eerrm. I guess he argues that some Warlock builds can have nearly free Hold Monster as Invocation, but I find giving free Telekinesis potentially much more powerful.
I'd say if he really wants it, you can give it to him while toning down the potency...
a) by putting a cast limit (like 1/short rest);
b) adapting the spell itself, such as limiting it to Medium creatures at most, or objects of 500 pounds max.
I see little sense in limiting range or duration, so it's basically the two variables I see you can play with.

Last option, just give it straight to him while warning him that you may fiat some things he'd want to do because you consider it too powerful.
The problem with this is that you both need to stay open-minded, otherwise he could feel it as arbitrary and directed against him.

So were I in your place, I'd rather go with the toned down version.
Hope that helps.

EDIT: Back on topic of custom spells, my "best" advice would be to a) think about your concept, b) once you are clear about it, look for an official spell that would be the closest in fluff or effect, c) start from here and adapt level depending on the differences in damage/additional effect between official spell and your own. Should work in many cases. :)

[MrStabby]

Bear in mind that there are other options to adjust.

Use an action to inflict more damage

Use a bonus action to do more damage

Use a reaction to impose a disadvantage

Add a smoke effect to obsucre things

(mentioned) change the radius

Change damage type (fire is often resisted)

Remove/add concentration



Some of these are big changes, some are small. You can certainly fine tune spells.