The Zerg had a large number of Hydralisks that were effective against air units, so they did not build any Spore Cannons that had anti-air and air-stealth functions. Therefore, when all the Overlords were eliminated from the battlefield, the Zerg instantly lost the ability to detect stealth units. Furthermore, the Zerg larvae could not hatch without the nutritional support of the Overlords, so the Zerg could no longer produce soldiers and send them into battle non-stop like they always did!
Uraki instantly saw the chance for victory! He immediately dispatched three Arbiters to the battlefield.
The energy reserves of the three Arbiters were almost completely exhausted, so they no longer had enough energy left to perform their signature 'Stasis Field' and 'Recall' skills. However, their perverse passive skill, 'Cloaking Field', which could make all nearby friendly units invisible by refracting light, could still be used as it did not require any energy!