Updating the OP to reflect this...
Does the 33% chance for +5 damage stack? Does the +5 damage stack? Regardless, this would be bloody amazing in Blessed Pegs. Vader Saders would love it too.
The +5 damage does not stack, but the +33% chance does.
The chance stacking is geometric. E.g. chance = (1-(1-1/3)^stackCount)
1 stack = 33%
2 stacks = 56%
3 stacks = 73%
4 stacks = 80%
5 stacks = 87%
6 stacsk = 91%
This interacts with adrenaline the way I think it interacts with adrenaline, right?
Ya, its a potential balance issue under current code (see adrenaline interactions with hammer, shortbow, and dagger)
...so ya, this on a chrysaora (0 ATK base -> 5 attacks on adrenaline) would deal (on average):
8.3 damage (1 stack) - 3 cards
13.9 damage (2 stacks) - 4 cards
17.6 damage (3 stacks) - 5 cards
20.1 damage (4 stacks) - 6 cards
21.7 damage (5 stacks) - 7 cards
22.8 damage (6 stacks) - 8 cards
Note: with a single stack of this buff, the average damager per attack bonus is +1.66.