What counts as a spell?

[otti]

For example the sorcerer that casts fireballs. Is that an attack or spell?

[gustavodeluxe]

attack damage is your basic attack. So yes, basic caratctere attack
And all extra attack from leveling up as meteor fall, or lighting chain etc... are spell damage

[Zeel Ara]

Anything that says "Spell" on the tooltip is a spell. If it doesn't specifically say "Spell" then it isn't a spell.

[Kuchi.Gyz]

You can get an upgrade for your basic attack from 1 god per run. This is NOT a spell. Everything else is.