Balefire

You point your finger, and a pencil-thin beam of white-hot light, so bright that it makes the sun seem dark, leaps instantly forth. The balefire slices neatly and hotly through any material or object, out to its maximum range or until it strikes a living creature. A creature struck by this beam is utterly destroyed, vanishing in a fading haze of motes of light.

Balefire does not just destroy its target instantly - it actually destroys it back through time, as the creature's thread of fate is literally burned out of the very fabric of reality. The "backburn" given by this action affects how far back in time the target's actions are undone. Everything the target did over that period, and everything that resulted from that target's action's, is undone, leaving only the memories of those who witnessed the target's actions. For instance, if a cultist is struck with balefire seconds after inflicting a wound on a hero, not only is the cultist utterly destroyed, but the hero's wounds would disappear.

Because of this backburn effect, balefire is seen as the most destructive act in the known multiverse, and many consider it criminal to even learn the spell at all.

When you cast balefire using one 9th level spell slot, the range is 25 ft. and the backburn is 5 seconds. The target can avoid balefire on a successful DEX save.

You may use this spell with concentration to sweep the beam, slicing through objects and one creature per round of combat. If you use concentration, you must expend additional 9th level spell slots equal to the level that you are casting balefire at. For example, if you are expending five 9th level spell slots to ensure a 1 day backburn, you must instead spend ten 9th level spell slots to sweep the beam into your next round of combat.

At Higher Levels. To cast balefire at higher levels, your character must spend additional 9th level spell slots. When you you do so, the spell's range and backburn effect increases. Two 9th level spell slots makes the range 75 ft. and the backburn 1 minute. Three 9th level spell slots makes the range 150 ft. and the backburn 10 minutes. Four 9th level spell slots makes the range 300 ft. and the backburn 2 hours. Five 9th level spell slots makes the range 600 ft. and the backburn 1 day. Six 9th level spell slots makes the range 1,200 ft. and the backburn 10 days. Seven 9th level spell slots makes the range 1 mile and the backburn 30 days. Eight 9th level spell slots makes the range ten miles and the backburn 6 months. Nine 9th level spell slots makes the range 10 miles and the backburn 2 years. Ten 9th level spell slots makes the range 100 miles, and the backburn is 10 years.