No, I think you are confusing the lesson I taught you Trips.
I always build the damage dealers up first to provide max damage.
6 Star Frozen Banshee with Lifesteal Gear + Warmaster will self heal to max in Clan Boss.
6 Star Frozen Banshee will do far more damage vs. 5 Star Frozen Banshee.
The only time FB will die is when the CB ramps up to high damage.
By the time the Clan Boss ramps up his damage to high, The whole team will die.
I build champion's up in the following order:
1st - Campaign Farmer -----> AOE Damage Dealer -----> Viking is using Elhain for this.
2nd - Clan Boss Team ------> It will have 5 heroes -------> I build them in below order:
A ---> Damage Dealer -----> This hero is the Poison hero - Kael or FB or Another Poison Hero
B ---> Attack Down --------> This hero is to keep the above hero alive doing damage longer
C ---> Weaken -------------> Some newer players don't run this unless there starter is Athel.
D ---> Defense Down ------> This hero is to improve the Pyschical attacks Damage.
E ---> Support -------------> This hero tries to keep the team alive or cycling moves.
The Supports are built up last because they often can function at level 50.
They don't always need to be max level in order to do what is required of them.
If the OP Starter was Kael, I would agree with you & L9753.
If the OP had Kael at level 60 instead of Elhain, I wouldn't build Frozen Banshee.
I wouldn't build her because in my mind Slot A has already been filled.
Slots B, C, D, & E are still empty.
I would move down the list to fill the Empty Slots before trying to Improve filled Slots.
The OP has no Attack Down hero ---> Can't fill Slot B move to Slot C
The OP has no Weaken hero --------> Can't fill Slot C move to Slot D
The OP has 2 different Defense Down heroes Uugo & Warmaiden.
I would tell the OP to pick 1 of them.
If the OP was to pick Uugo, It would be fine to me Slot D would be filled.
The OP has Vrask as a Support for Slot E
All the Slots have been gone through 1 whole time.
I would start over from Slot A to see if I can improve on what is already there.
At this point, I would recommend building Frozen Banshee to replace Kael.
In the OP situation, none of the above happened, The OP picked Elhain.
Elhain is a Damage Dealer, but has no business in Clan Boss
The Damage Dealer the OP would want is a Poison hero so Frozen Banshee is the one he would want to build up.