I’m not sure how it distribute but not everyone who attack boss will get the cube.
However, The boss died from everyone effort. What if we change it as different cube per participants?
Ex. Top xx dmg and party dmg will get the purple cube.
The rest who helping will get another cube that have lower chance of rare item or something else.
I like the ROTMG system where, for itens that could be dropped for everyone (like the cube), you need to pass a threshold of damage (lets say 5%) to be qualified for a % of chance to drop it.
Now, for other itens, the % of damage you make would like your % of damage. Therefore, the guy who did most of damage gets the privilege, but also, other people that did any attacks still have chance to get it.
My full support wiz-cryo-linker3-alch is very sad, Rizzou.