From Archon Arcana - The KeyForge Wiki
Champion Anaphiel has the Taunt keyword and is therefore placed forward in the battleline

If a creature has the taunt keyword, any of its neighbors that do not have the taunt keyword cannot be chosen to be fought by an enemy creature that is being used to fight. In the battleline, taunt creatures are slid slightly forward to indicate their presence to the opponent.

KeyForge Master Rulebook v16 November 2022


Taunt should only prevent choosing the creature that is protected by taunt. If you choose a creature which results in the battleline changing such that the chosen creature is now protected by taunt, it will still be available to continue the fight.