[X] Loudly yell "DAEVA! remember those illusion things you made? can you use them to communicate with us?"
if the Daeva does not respond, next try matter-molding those words. if that doesn't work, give up on that and do whatever other people said.
you know, just in case the Daeva hasn't already thought of that- we know the Daeva can see us when we're not nearby and runs some of the combat numbers, so unless there's a new combat system here Daeva can probably still see us. or maybe the Daeva generates the flavour for combat activities like [flickers itself around]? or they could edit the entries for everything to whatever message they want to send and wait for us to scan something?