Cecil, Kain, and Rosa arrive in different forms and are obtained via different means.
If Kain and Rosa are found via the Summons system they make for powerful team members, with equally complicated relationships.
To have a chance of uniting Cecil with Kain and Rosa during this collaboration event, players should look no further than the Summons system.
UR Demon Wall grants a new esper upon its initial summoning and, boasting unique card art, can achieve higher attack stats by having Cecil, Kain, or Rosa equip it.