Swords of Revealing Light cameo.
Also, I guess this is where Crowley's path goes wrong. Crowley overexerts himself for the others, as seen in Alpha Summon, and the summons, maybe including this dragon, take over as seen in Omega Summon. Somehow Crowley ends up sealed and used by the Spellbooks as a power source. Given Endymion and Crowley are friends, the future animosity between his kingdom and the Spellbooks might be because of them abusing Crowley.