You can walk to the campfire while Shakarr is in the other side of the campfire, and that will buy a little time for you to drink HP pots.
Notes
This is a solo-only battle.
You will be automatically transformed into your path skill choice (Paladin or Dark Knight) for the entire duration of the fight. This includes the 2nd Transformation.
However, you will not gain any Path EXP.
Both Conviction and Fissure has a 70 second cooldown, as opposed to once per transformation in other battles.