Sao is not the first to use it
Comment by Original critique on Logout shita no wa VRMMO janaku Honmono no Isekai deshita Genjitsu ni Modotte mo Status ga Kowareteiru Ken - Chapter 1
1 Reply
@Original critique all these people forgot about dot hack, Tower of Druaga: The Aegis of Uruk were the og's of the sword art online