BiFrost: Auras

I had an idea.
I was thinking that the world lacked internal consistency.
Where did the powers for the spells and the class abilities come from? The Hero's health for the second wind and action surge, the Prowlers speed for the cunning action? Those who've never been through a BiFrost do not have a class. So what gives those who have their power?

The BiFrost that makes them delvers gives them that power. It infuses them. And when they use their powers, a bit of its power shows itself. Earlier I talked about spell effects and now I'm going to update them. I decided each subclass shouldn't get its own spell effect though, that might muddy it. But perhaps each spell gets its own flavor as its already described in the PHB.

Brawler - Glowing fists
Dynamo - Heat waves of energy off the body
Hero - Glowing eyes and blood
Hunter - Animal spirit overlay, tusks, snout, fur, feathers, etc.
Incarnate - A halo around head and wrists
Juggernaut -  Fissures of light across skin
Knight - Small and vague spectral wings of light
Mage - Glyphs and circles appear almost tatoo-like on the skin
Naturalist - Spectral plants appear
Performer - Spectral mask
Prowler - Light from soles and palms.
Witch - Spectral horns

The effects only show up when casting a spell or using a feature (cunning action, ki power, action surge, casting a spell, rage, etc.) It doesn't work come out for always ones like weapon style or the extra damage on a monks unarmed attacks.

Visual effects can be suppressed if you also concentrate? That makes it too easy for fighter types, though does mean raging barbarians can't hide it, which I like.