This bit on Piecemeal isn't as much a flaw in game play as it is a flaw in concept (in my mind). I do not like mindless automatons being called golems, in my mind a golem is a truly terrifying religious entity. The automatons in most FRPG's are just ye olde robots.
In Piecemeal this is separated. The "Classic RPG" golems are created by wizards (Simulacrum) and have all kinds of fun options of binding spirits, demons, dryads or the like (willing or maybe not) into the simulacrum for all the fun of "evil scarecrows" or "stone golems" from FRPG's.
Priests can craft a golem. Golems are not defined by their material, merely by the standing of their creator with their deity. Golems can be forged with whatever is appropriate to the deity, it isn't the physical form that holds the creature together. The golem is fueled of divine power.
The ritual takes a full two days (no sleeping) and a lot of Piety. So what physical effects does it have? To convert to D&D terms the golem has attributes based on a 1 to 1 score of the priest's "Caster Level", it regenerates damage each round based upon that level, and it has a damage reduction equal to the caster level. This makes it a combat powerhouse that is nigh indestructible, like the golem of legend.
Whats the flaw then? Well unlike the D&D golem this is not a controllable creature. It is intelligent and acts on its own accord to its goal, slaughtering everyone who doesn't follow his creator's deity (though it will not harm the faithful). Its mute, it doesn't talk, but it isn't stupid. Think more "The X-files" and less D&D.
What is its flaw? How do you defeat such a killing machine? The first option is the priest who created the golem can create a control item (he doesn't have to). It doesn't give you control of the golem, but destroying the item destroys the golem. Brute force is highly unlikely to succeed except for very weak golems made by lower level priests. The final way is that the golem is tied to places of worship and holy ground of his deity. If he is removed too far from those sites (or the sites are all destroyed or defiled) the golem is again destroyed.
What does this style of golem allow?
Combat encounters that are not about killing, but about surviving and outmaneuvering the opponent. The golem becomes less of a "stand up and fight" adversary and more of a "Jason Voorhees" villain the PC's must avoid until they can crush him indirectly. This becomes even more so if one or more of the PC's are of the "correct" faith and can try and shield their "incorrect faith" brethren from harm.
It can also allow for tough moral choices. Building a golem can protect your community from hostile and evil forces...but it also isolates it (violently so) into a xenophobic community.
Welcome to your doom
8 hours ago