All enemies other than the Big Sad Lock are excluded from the enemy counter and spawned in the manners listed below as long as the Lock is present.
After 24, 48, and 72 seconds have passed: Few Nameless Elite Knights
After 110, 130, 150, and 170 seconds have passed: Some Nameless Elite Knights, few Greytail Leaders, and (possibly) several Theater Golems
After 196 seconds have passed and every 16 seconds afterwards: Many Nameless Elite Knights, some Greytail Leaders, and several Enraged Tombkeeper Grotesques and/or Theater Golems
When the barrier is generated for the first time and every 20 seconds while the barrier is present: Some Nameless Elite Knights and few Mudrock Zealot Leaders