Pushing and Enhancing Spells
Any spellcaster can tap into their reserves of magic to attempt to push through an enemy's defenses, or to alter their spells on the fly to meet a situation or do things that the spell normally couldn't do. These taxing maneuvers are referred to as Pushing or Enhancing a spell.
Spell Pushing
A spellcaster may push a spell, recklessly tapping into the ambient forces of the weave with abandon. After casting a spell that makes an attack roll or provokes a saving throw, or after making an ability check as a part of the spell, you may roll a 1d4 and add it to the attack roll or ability check, or subtract it from a single target's saving throw. You can use this ability a number of times equal to your spellcasting ability modifier until you finish a long rest.
When you Push a spell, you must then make a Constitution saving throw of DC equal to 10 + the pushed spell's level. On a failure, you must spend hit dice equal to the spell's level, plus 1 additional hit die for every increment of 5 you fail the save by, or gain 1 level of fatigue and strife, plus 1 level of strife for every increment of 5 you fail the save by. If you do not have hit die to spend, you gain 1 additional strife.
A caster may use any number of their spell pushes at once, adding 1d4 for every use expended. For every additional push used at a time, increase the Constitution save DC by 2, and the base number of hit die spent on a failed save by 1.
Spell Enhancing
A more dangerous and powerful version of pushing a spell, a spellcaster can unleash their full strength on their magic, bending it to their will. You may add any single metamagic effect, or another similar creative effect of your choosing, to a spell. A single spell may benefit from an Enhancement and a Metamagic effect simultaneously, even if they normally cannot. After using this ability, you cannot enhance a spell again until completing a long rest.
When you Enhance a spell, you must make a Constitution saving throw of DC 15 + the enhanced spell's level. On a failure, you must spend hit die equal to the spell points the metamagic feature you mimicked would normally cost plus the level of the spell, plus 1 additional hit die for every increment of 5 you failed the save by, or gain 1 level of fatigue and strife, plus 1 level of strife for every increment of 5 you fail the save by. If you do not have hit die to spend, you gain 1 additional strife.
If the Enhancement does not have a spell point cost, the DM can set it (usually between 1 and 5.)