Converting undead to construct (PF)

[Rift_Wolf]

I'm working on a campaign with an army of Green Star constructs preparing to take over the world. However, at low level constructs are pretty thin on the ground.

I've been looking specifically at the Graveknight template, and though about converting it from an undead creature to a malevolent construct (*cough* BORG *cough*) that begins overtaking cultists as the first wave of destruction. Before someone points out Graveknights have to be at least CR4, I'm aware of this, and will be breaking out the nerfbat if they seem too powerful.

My main question; what should I be aware/cautious of when changing an undead to construct? The following factors are things I've been thinking about;

• Constructs don't benefit from a Constitution or Charisma bonus for HP.
• There are fewer spells, feats and effects that deal with constructs as opposed to undead.
• At low levels, the +20HP for being a medium construct would be much better than the regular hp bonuses.

Is there anything else people can suggest? Or point me to some template (Other than half-golem) or homebrew that'd fit?

[bobthe6th]

as this is really low level, arbitrarily assign HP totals?