The Boss’s Health Track operates differently than Minions’ or Heroes’ tracks do. It has multiple markers (one for each Minion), each of which is moved independently, and the goal is to get all Health markers to zero. When applying damage, one marker can be moved the full amount of damage, or the damage can be spread across multiple markers.
For example, dealing 3 damage could be applied to one marker, split up between two, or even split between three!
You may choose to move 3 different Health markers 1 space instead of 1 marker 3 spaces.
Health markers cannot move onto or past a track space marked with an Altar icon unless there is an Altar Marker placed there. The Boss absorbs any damage, including partial damage, to reach that threshold, but is not hurt by any remaining damage that would match or pass an uncovered Altar space.