Be carefull wich rares you sacrifice, especially void rares, who are harder to obtain again, void shards are scarce. I would keep 

• Bellower, great for Ogryn Faction wars. Bellower in a stun set is such a fantatsic champ vs. the nasty 3 Stehalia + 2 Thenasil waves, that can block your progress in fw otherwise. And Bellower may return in DT hard, where similar waves pop up from time to time
• Paragon, the unkillable dude, Spider teams can be build around him
• Renegade, her decrease cooldown fby 2 turns is remarkable and you don't have Prince Kymar
• Reliquary Tender, my key to beat the Nether Spider in DT
• Dagger for AoE decrease def in faction wars. Banner Lords have only few champs with that ability, and you don't have Stag Knight
• Soulbond Bowyer, not void, but great damage dealer and 100% tm decrease in faction wars

Thank you very much Skadi, don't worry though, I haven't sacrificed a single void yet unless it's been a dupe. All the voids you listed above are safe and I have plans to build them for future ☺️

From a Clan Boss perspective I'm interested in Sepulcher here. Then, I think I want Orn or Ronda, though I'm not sure which. I think Orn would be great for Dragon farming, though. 

To answer your initial question, who to rank up next, I think Sepulcher is a great choice for CB.

I see a team consiting of 

• Sepulcher (aura, decr atk, def buff, stun remove)
• Anax (decr def, weaken, poison)
• Geomancer (damage)
• Runekeeper Dazdurk (leech, heal)
• Toragi (decr atk, ally protection, shields, poison)

As second champ beside Sepulcher, I would go with an AoE damage dealer. The only real hitter at rank 6 is Elhain so far. Magnarr or Ronda would fit.

Ronda seems to have more overall utility, her block active and passive skills is just god tier in arena. An argument on Magnarr's side is his affinity. Ronda and your actual AoE damage dealer Elhain are both magic, Magnarr as spirit champ would cover their weakness in force affinity dungeons. And, important in higher dungeon levels, as hp-based damage dealer, he has great survivability

Really appreciate the feedback folks, I had fodder ready a few hours ago but wanted to make sure sepulcher was a solid choice. Looks like sepulcher and Ronda will be my next rank 6's then. I'm quite interested in seeing sepulcher's mechanic in play, and Ronda being able to bypass udk in arena just sounds like a nice weight off of my shoulder for sure to annihilate ress champs, as long as I can get damage high enough on her ☺️ After this, a lot of food farming to get rest of champs 6'd! 

After sepulcher and Ronda I'll definitely be looking to speed up drag runs, auto is consistent victory but takes 4mins 30 on auto, would like to see that move down to 3mins a run for convenience of battery life and my overall sanity☺️😂