D&D General Folkloric Magic?

[Coroc]

There's already two player-accessible Rain of Colorless Fire type spells officially (in 3.5e at any rate). Apocalypse From the Sky is a ninth level corrupt spell from Book of Vile Darkness, and Rain of Fire is an epic spell from the Epic Level Handbook. The former requires an artifact focus and deals serious backlash to the caster, and the latter requires an epic feat and a DC 50 skill check

Yea sounds good. N.p. to housemake these for 5e, yo ujust have to tune things a little. I rule that these kind of spells (if available in my campaign) are something like 10th level magic, they either require a scroll, or if a level 20 mage wants to remember this from his spellbooks, then he has t olet go his 6th to 9th slots for it to fit into his memory.

Of course this kind of magic is always supedangerous and if someone friendly around gets killed by using it, he might get killed instantly and / or for good.

A level 20 mage also is not totally immune versus domination spells and effects, so as long as he memorizes such a thing he is a walking living nuke. The only safeguards are that these spells are mostly rituals, require certain context circumstance and preparation, no matter what the casting medium is.