Meta Mage

Having knowledge of the fundamentals of this universe, you can can manipulate the weave with greater ease then other mages.

Once per long rest, you can work on making a new spell. By combining two spells of 1st to 4th level. Make an Ability check  useing your Primary spellcasting stat with proficiency, against a DC of 15.

 You can use any number of effects in any manner you choose. 

The number of effects any given spell can have is 3. This includes damage. 

Any new spells damage cannot exceed that of a Fireball at 8th level. (13d6)

The spell becomes a level equal to the spells combined level, and cost that spell slot to use. (4th + 4th = 8th)