Unlike common enchanted objects, Golems needed to move around, follow orders, and choose the best spells to use according to the instructions they received.
Fueling even a limited artificial intelligence required a massive amount of energy that no number of crystals could provide during a fight. Golems would lose power as they fought and needed a long time to recharge unless provided with an energy source like an array.
The fourth set of runes prolonged their autonomy in battle and reduced the time they needed to refill their mana reserves.
The fifth and the sixth set would respectively absorb part of the kinetic and magical energy that would hit the Golems during a fight, turning them into a protective energy field.
The seventh and eight set had similar properties but different functions. The former would carry Lith's and Solus' telepathic orders in a form that the Golems could understand while the latter replaced the nervous system.