The Last Guardian

His Excellency's obsession with getting revenge against the Guardians causes him to have engineers build their own portal tech which doesn't work with the Guardians' tech. The result is the capture of a Guardian child Adele who is educated to be an assassin. His Excellency's only use for this last Guardian is to wipe out the royal family ruling the City of Paradise. As he reaches more goals, there is betrayal brewing in his own household which results in more death, destruction and important people escaping to the safety only the Guardians can give.