No, Zagan killed Andras (Barbatos' teacher and ancestor) when he was 8 years old, and then he was given Marchosias' Sigil when he was 18 (around May in the story).
The incident involving the demons, where half of the Archangels died, happened months ago (in February), but it's been years since the last time Orobas and Marchosias met.
In summary: February (demon incident) - April (start of the story) - July (Bifrons' ball) - October (current arc)
Not Fluff, but I can share some of my issues with volume 6:
Now, good things about this volume:
I'm trusting Itagaki Hako with the adaptation of volume 6, but I hope it doesn't get much time to be adapted and we can move to volume 7 soon.
"Who would buy any souvenir modeled after this girl?" says the one who chose a cup modeled after his crush the same girl he's talking about.
Thank you very much for the chapter. Chapter 73 will be released next week in Japan, beginning the adaptation of volume 6.