Hi there!

I see you have some great champions which could make an awesome clanboss team! First off, you definitely want to use your Legendary champion Vizier. He can extend all the debuffs and does an amazing job at that. Poisons on the clanboss deals a lot of damage, so your Epic Occult Brawler could be a great pick for that. The 2 rare undead sisters are also great at doing poison damage but I haven't tried them myself. Your epic Peydma could bring a 50% decrease attack debuff which will make you survive longer, especially in the later rounds. Your Epic Steelskull can bring some valueable heals, increase defense buff and has poisons on his A1. The last champion should probably be someone who brings decrease defense/weaken, which will increase your damage on the clanboss significantly. It also helps a ton if you got your champions fully upgraded with masteries and the Warmaster mastery. It's a good idea to keep everyone in the lifesteal set for more surviveability. When the Warmaster mastery procs and deals a lot of damage, the lifesteal set makes your champions heal for a lot! 

Good luck, and have fun!

use bulwark,  Vizier , Occult Brawler , frozen banshee,  doompriest or apothecary.  make sure you gave all of them speed 180+ ton of accuracy . apothecary dont need any accuracy tho.  make sure   your heros attack in a serieal apothecary first then vizer,bulwar than banshee then occult brawler. occult brawler dont need any book. tru this formation.