Lv 15 Angvoth
When entering this boss, the number one thing you should keep in mind is how many minions Angvoth can summon at a time. He will summon close to a dozen cultists at the beginning of the fight and keep spawning them in smaller groups further into the fight.
Another main gimmick you should know is that when Angvoth is glowing he takes reduced damage, and sometimes he even heals when attacked. He will glow for only the first minute of the battle, which is the time in which he attempts to defeat you with his army of cultists.
When Angvoth decides to jump down from his altar to fight you face to face, you need to be aware that he moves pretty quickly and that he has a handful of ranged abilities. Making sure that you can space him out with movement, ranged gear, knock back items, etc. is the best course of action and often leads to the success in this battle.
Finally, Angvoth has a Miasma that grows during the fight and after a given time, he can kill you outright with it. This can be easily countered by going into the fight with good DPS.
Lv 14 Ratface
TBD
Lv 12 Spider Queen
TBD
Lv 18 Lucius
TBD