The military expert group (a genuine expert group, organized by the command center with the entry requirement being participation in wars and campaigns in at least twenty different worlds, and each one is incredibly aggressive) believes that the Fallen Apostles suffered huge losses in this invasion. According to the intelligence gathered, they deployed at least half of their national reserve forces. Due to the direct involvement of the Father God and King Huron, coupled with Sandora's sudden outburst, the enemy directly lost two group armies— and these two group armies almost gained no results, unless scaring me counts as a result.
Their losses at other invasion points were also significant; even being feints, they left behind wreckages of thousands of medium and large warships and countless light warships under the fierce counterattack by the local defense army and the Empire's main force. Altogether, it equates to losing three group armies in this invasion.