Board Thread:General Discussion/@comment-32237043-20160626014030/@comment-86484-20170607134805

Canon proven in the game? Show proof then.

The question was "does Sans have 1 HP at the time of the battle?", and all signs point to "yes".

If you change the question to "does Sans (or anyone else for that matter) always have 1 HP/a fixed amount of HP?", then the answer is "no".