So you most likely are wondering what legendary item drop I got from this boss and I have a picture to show you as well as I'll explain how it works.
But before I travel too much off topic I have seen three different types of bosses. The first was the one I shot the video of in mausoleum chapel 3rd floor which was mostly melee aside from his AoE that he does. On floor one of mausoleum chapel a ranged world boss with a bow pretty much hits like a truck and does arrow rain. I didn't get to record that one because the server was pretty much a lag fest and the bosses arrow rain was pretty much slaughtering everyone and I got killed a few times just because of pulling aggro. In the first floor of the mausoleum (there's another mausoleum at level 81+) I saw a magic caster world boss I didn't get to really video that one either but that one was pure murder I spent more time dead on the floor then doing damage.
We aren't too sure how the distribution for the loot table for the boss is but there's a few things we do actually know which will be helpful for when you do a boss. People who do damage to the boss but die during the fight that resets the participation you did in doing damage. So you want to avoid dieing because if you do a lot of the damage but die you have to go and do more damage again to be considered for drops. The loot comes in the way of a cube which is opened for a RNG chance at something good. Most of the items that come out aside from weapons are mostly used for vendor money. Example Talt <- Vendors for 5k if you sell it to anyone for less then your doing it wrong. But people do that pretty often because they don't check the vendor prices. Silver bar is 30k vendor as well. Some of it can also be used for high level recipes but never sell those items for less then vendor price.
We don't exactly know whether healers get participation based on healing. It was brought up in the forums but no one could give a straight answer about it but if your party does enough damage you should get rewards. We did make suggestions to the developers about doing something for healers if they can't find a party. But we also don't know if the boss has a limit on payload like for example the top 20 people getting loot ect. Cause it doesn't seem like every single person gets loot.