You may use your down time to research the effect your spells have on the weave to discern a possible way of merging two old spells into a new spell.
Research requires one work week of work and at least 100 gp spent on materials, bribes, gifts, and other expenses.
Typically, a character needs access to a library or sage to conduct research.
After a work week of research, a character makes an Arcana check with a +1 bonus per 100 gp spent beyond the initial 100 gp, to a maximum of +6. In addition, a character with access to a particularly well-stocked library or knowledgeable sages gains advantage on this check.
All spell categories have a d12 rolled for either side, the highest dice wins, this is repeated for each category. You can gain additional d10 to add to categories of your choosing. (like advantage or the risk boardgame)
If both dice tie, you get a combined effect, that is greater than either alone. (for example, a range of 10ft spell with a range of 60ft spell, would combine to equal 70ft
1-10 = you fail! The spells backfire, causing you harm.
11-15 = you fail but gain insight, so next attempt you get advantage.
16 = you pass! You gain 3 die to weight in your favour.
For every 3 points beyond 16 you get 1 dice to stack in your favour. (rounded up)
You also will get 1 additional die, per spell that you have previously used to merge. As you have knowledge of this spell already.
You can gain 7 extra die by increasing the spell level by any amount or lose 7 die to reduce the spell level by 1. A spell can only go 1 level lower than the highest-level spell used to create it.
All created spells must be at least level 1
Below are the list of categories rolled during spell creation:
Area of effect.
At Higher level. (when applicable)
Damage type can include heal/buff. the catagories may need adjusting depending on the spells being used.
Any new spells you create, you are entitled to name, and it will have your name somewhere in its name (eg, Tasha’s hideous laughter).
They will be added to a seperate spell list, that will be linked under the Magic page and menu navigation. Spells on this spell list are only known by their creators, or those the creators teach them too. A list of all players who know the spell will be kept on the spells page. Alternatively you may decide you want you new spell to be common knowledge in which case all may learn it and it will be added to both the previously mentioned spell list and the correct classes spell list.
It is worth noting that spells created in this way can not be stored, or used to enchant.
Finally spells created in this manner DO NOT have a spell level, instead they merely have a spell point cost. Meaning you could learn a 14 point cost spell at any level.
Image – http://towerofzenopus.blogspot.com/2014/09/prismatic-spray.html