A quick guide to genestealer cult generations.
1st generation
Here are two 1st generation genestealer cult hybrids. 1st and 2nd generation hybrids are the hardest to tell apart. The key places to look are their feet and their heads.
The first generation hybrids have a spike on the heels of their feet, which the second generation lack. The first generation hybrids also have larger crests on their foreheads.
1st generation hybrids most commonly have 3 arms, but very occasionally can have 4. Like on the unit leaders.
2nd generation
Here are two second generation hybrids. Note they have rounded heels on their feet, rather than spiked heels like the 1st generation hybrids. Also the forehead crest is smaller and less well defined than on the 1st generation models.
2nd generation hybrids seem to always have 3 arms.
3rd generation
Here are two 3rd generation hybrids. These are fairly easy to tell apart from the 4th generation, due to their hunched posture and bulbous heads. Also the exposed skin on their arms retains some alien features, like ridged flesh and clawed fingers.
3rd generation hybrids most commonly have 2 arms, but sometimes can have 3. Such as on the heavy weapons models, or the primus.
4th generation
Here are two 4th generation hybrids. Quite easy to tell apart from the 3rd generation hybrids. They have upright postures, and no obvious alien features aside from the forehead crest.