How would I go about creating magic orb that looks like from magic menu in Skyrim in Unity3D?
Here is what I have in mind: Orb Image
And a video of that effect from 0:09-0:13: Orb Video
It is likely a combination of different particle effects.
A particle effect is a graphic effect which consists of many tiny objects which move according to specific rules. In this case it looks like they combined some particles which orbit around the center with some which are created at the center and move out of it while becomming more transparent and others which ares spawned outside and move towards the center while becomming less transparent.
For the rendering of the particles themself they likely used lots of shader effects like blur, bloom and different transformations.
My guess is it was a pre-rendered. But I could be mistaking.
If it wasn't pre-rendered (and still likely if it was), I would guess that it's done with a series of steps: