Magic Storm - Character Deck effect.

it does work, it just falsely shows on your damage range. to explain it simply, let's say the bonus is of 1000 damage. and you're a dark knight with 10k range, 200% impale and 1.6x zerk.

your range will look like this: 10 000 + 1 000 = 11000 range.
you'd expect to deal: 11000*1.6*2=35200

however, the effect doesn't work that way, it actually grabs your real range, calculates the damage, then adds the 1000 bonus, like this:
10000*1.6*2=32000
32000+1000=33000

so you'd be dealing 33000 damage with the bonus, against the 32000 damage without it, big upgrade huh. notice how horrible it is?

Wait, it's just a flat bonus at the end of everything? Ahhhh, my warrior deck has been a lie!