tried my 3rd sirius and failed again on the last phase. he just destroys me in almost 1 shot =_=
You've got low amount of life on rings / gloves, no endurance charge crafts, no anointment on amulet, no culling strike and only lvl 20 ed gem.
Up your life as much as you can to minimize chance of 1-shot, get corrupted blood immunity gem and some source of culling strike, and most importantly glue yourself to sirus and always follow him when he jumps around. Most deaths people have are from losing track off him and then getting beamed from 3 screens away. Keep ED up on boss to keep the heal rolling.
Also btw if you put 1 extra point below fangs of the viper and connect tree there you can unspec 2 points below coordination and get 1 extra free point, if you need strength, prowess is better than the 10 small node.
thanks for advice about passives, working towards better amulet and then rings.