I would think it defeats the entire purpose of the new concept if they put a time limit on it... this event is intended to just showcase the system so you can get Hordin very quickly, but moving forward the idea is to acquire fragments of a champion over a period of many weeks or even months, no? 

Hi.

Trips said:

is there a time limit on summoning these? Or can wait until a champion chase event to summon our hordin book?

L9753 said:

I would think it defeats the entire purpose of the new concept if they put a time limit on it... this event is intended to just showcase the system so you can get Hordin very quickly, but moving forward the idea is to acquire fragments of a champion over a period of many weeks or even months, no? 
Besides, if there was a time limit it would have been mentioned somewhere. 

L9753 is correct. Over time, there will be more opportunities to gather Hordin’s fragments. The current Hordin event was a test for the mechanics of it all. Soon there will be a new champion to summon, so stay tuned.

Have a nice day and stay safe.