Artificial soldiers made of earth, stone or wood, which Avicebron manufactures. The concept of golems traces back to Ancient Israel, and the basics of their manufacture are said to have arisen sometime between the 2nd to 9th centuries. However, if you trace it back further, golems originate from a passage in Genesis that says “The Lord molded man out of the dust of the ground and breathed life into him through his nostrils.”
In other words, golems were originally an attempt to make “humans.” Therefore, their quality is considered higher the closer they are to being human. However, that is only the ideal golem in Kabbalist thinking, and regular magi might simply devote themselves on “how to make a strong golem.”
Avicebron’s magecraft is fundamentally specialized solely for the sake of making golems, and his techniques have already reached a level that modern magi cannot catch up to, letting him spend his whole life playing around while living off just the sales from his golems. It’s only natural that Roche idolizes him.
To make something close to human is the concept of Avicebron’s golems, but he’s willing to make completely different kinds of golems to amuse himself as well. The steel horse he made to act as Vlad III’s steed was a simple yet prided product of his, and even just the gems used for its eyes were worth hundreds of millions.
After the war, some of his golems actually managed to just barely survive, and though most of them were sold off, a few golems went to a new land with the homunculi.

Fate/Apocrypha material: Fate/Apocrypha Encylopedia