Chain Lightning may have too much anti-army potential

[zlefin]

While I haven't gotten enough testing to be sure; it seems like chain lightning could potentially hit hundreds of creatures or even thousands in a massed army.
none of the other spells seem to have quite as much potential to wipe an army, though aoe is of course great vs armies. But chain lightning could kill every enemy in a 500-foot radius as long as they're close enough to make a path through them all. (and in an open field environment so you can get line of effect to them all).
It just seems like an excessive potential compared to the other spells I've seen.

[Xenocrat]

Yeah, I noticed that Chain Lightning can do that if you face hordes of mooks who autofail even on a 20. Not hard to do in the low teens as a Wizard.

But the problem already exists for Horrid Wilting, which has the same 500' range, no target limitation, and no way to cut it off early. Arcane AOEs have this weird thing where they're not great against level appropriate foes but can (in two instances) auto kill entire battalions of scrubs.

[vestris]

Armies need counterspelling mages then.

[Colette Brunel]

By 11th level, chain lightning is not just a rock-solid spell for battering an entire encounter down with heavy damage. It is also a spell of great narrative power as well. An 11th-level druid or wizard is free to gaze upon an army on the march and then slay it in a span of six seconds by hurling out a chain lightning.

Everyone should have a read of this spell. Its anti-army potential is indeed ridiculous and narratively monumental. Just remember: there is no way an 11th-level barbarian or fighter could take on a whole army, but an equal-level druid or wizard can.

The rules for natural 1s and natural 20s are an absolute mess, but as far as I can tell, for skill checks and saving throws, natural 20s are not necessarily an automatic success as per page 292.

"However, if you succeed and rolled a 20 on the die."

Line of effect should not be hard given some elevation, such as from flight.