There's some sort of evil demonic creature below Karma that's pulling all the strings.

Dimentio's Ghost: Tch. All bite and no bark.

Now then, massive buffs, you say? Dimentio!

*dimentio casts a syphon spell, preventing karma from using magic of any sort*

And here weeee go!

*pulls out rocket hammer and blows self towards karma with rocket blast while dimentio casts a binding spell*

*fires the triple rod through karma, then causes excalibur to fall from above, dealing damage and dispelling buffs, allowing me to summon the Charge 'n Targe and Quake Blade, charging at karma and utterly destroying nearly every health bar she would have*