Hit Points, listed in the Codex as "None", is a placeholder Health class. As of writing, it is only used by Maroo and by Councilor Vay Hek in all his forms. "Hit Points" is very similar to the Object health type in that it has no weaknesses or resistances, though unlike Object it is susceptible to Critical Hits.
Note that while Hit Points have no specific weaknesses or resistances, Vay Hek is considered to be armored with Ferrite Armor. Thus, he still resists Script error: The function "Proc" does not exist. and Script error: The function "Proc" does not exist. damage, but is vulnerable to Script error: The function "Proc" does not exist., Script error: The function "Proc" does not exist., and Script error: The function "Proc" does not exist. damage.