It's not so much that I wanted to be "non-mechanical" as that I thought the current wording was a simpler, more elegant way of saying the same thing. But if you both prefer the clunkier phrasing....
Forward to Clunkiville then!
How's this:
Yuan-ti Conditioning: If a yuan-ti uses a Charisma-based skill and mind-affecting power against a megalofolk it always succeeds, the megalofolk is not allowed a saving throw or resistance check.
Let's slap an (Ex) on there (I loathe untyped SAs/SQs) and reword slightly:
Yuan-ti Conditioning (Ex): A yuan-ti using a Charisma-based skill against a megalofolk always succeeds. A megalofolk automatically fails all saving throws againts the mind-affecting spells and abilities of yuan-ti.
I dropped the resistance check since it lacks spell resistance.
What about the description and background?
This megalobeing dons megaloarmor and wields megaloweapons.
Megalofolk are megaloriffic.
Megamazing but needs more megacontent.
They like tossing back Megalowenbraus while dining upon megalomein?
But seriously...
Megalofolk are clones of clones created from humans via yuan-ti experimentation. Each generation of megalofolk breeds slightly larger than its predecessors. Although originally the cloning process only worked on humans, yuan-ti have figured out how to create megalofolk out of histachii, and rumors persist that at least one pureblood found a way to clone himself.