At the end of the war Aleister said Fiamma's mistake was using the Christianism.
But now Birdway says Fiamma was going beyond the rules from Christianism.
Another Aleister's flip-flop? I wouldn't be surprised, he tried to kill Fiamma to avoid any other magician gathering any info from him and then just happens Ollerus and Sivlia pick him up to get info about Horus' age
.