When rifts can appear
The rift check starts after 75 seconds of run time. The check timer counts down for 30 seconds while eligible, so an uninterrupted first check is just after 105 seconds. Checks occur every 30 eligible seconds. The first chance is 20%, rising by 20 percentage points after a failed check, up to 100%. A living boss skips that attempt. No new rifts open from minute 28.
Enter and win
A rift stays open for 45 seconds. Moving close enough enters the arena and brings the co-op group. The arena lasts up to 120 seconds. Avoid telegraphed attacks while keeping your damaging slot active. Winning awards resources and a bond; losing or timing out returns the group without the win reward and lets the run continue.
The actual loot rule
A regular defeated rift legendary is also a boss: it drops ten boss coins worth five plus ten legendary coins worth eight, for 130 base coins, and three normal tickets. Judgment enemies are a separate XP-only path. The shared pickup logic awards an ×10 ticket with 50% chance for a rift legendary kill (one-in-three for an ordinary boss), rather than guaranteeing one every rift. Pickups still need to be collected.
Use the bond after the fight
The bond lets you fuse moves into one active slot so they fire together. Choose complementary coverage rather than assume every move always attacks. Consult the bond guide and planner before committing.