Most actions in each tier guarantees 1 of the 3 superior item drops. This thread explains it a little better http://forums.kanoapps.com/threads/raid-boss-walkthrough-and-feedback-thread.14761/#post-122276
The Raid Boss has 6 loot items, each with a Common version and a Superior version, the latter being stronger and rarer.
Everyone who does at least 2,000 actions with 1,000 of those needing to be Healing Actions will be awarded with a Loot item, Cash, and XP when the Raid Boss is defeated. The drop you get is determined by random, however under special conditions a player may be guaranteed a Superior item drop. For example, a player who summons their very first Raid Boss will always get a Superior drop if they succeed in defeating it.
or here http://forums.kanoapps.com/threads/raid-boss-3-feedback-and-walkthrough.14638/page-4#post-123230
Drops are random, but you can force a Superior drop if this is your first Summoned Raid Boss of the event or you have the highest overall actions in your level tier (the Boss owner also counts in this). Even though the drop numbers are random, having higher actions will put you in a better position of earning one. That is not a complete guarantee unlike the first two methods, however.
Last edited: Apr 17, 2015