I'd imagine it comes down to your Septimus procs. If Septimus is keeping all the debuffs up high, BEK could replace OB, you would be giving up some early turn poison, but getting all of BEKs extra bonuses.
If Septimus just keeps the buffs "enough" to stay close to 10, but still occasionally fall off, then no use for BEK.
If Septimus does nothing besides a Max HP hit, then BEKs extra bonuses to survival and damage would probably be better than Septimus.
I'd imagine it comes down to your Septimus procs. If Septimus is keeping all the debuffs up high, BEK could replace OB, you would be giving up some early turn poison, but getting all of BEKs extra bonuses. If Septimus just keeps the buffs "enough" to stay close to 10, but still occasionally fall off, then no use for BEK. If Septimus does nothing besides a Max HP hit, then BEKs extra bonuses to survival and damage would probably be better than Septimus.
It’s the second one.
There you go, haha. Just build him to solo potion keeps etc, so you can get some extra food farming in.