database > raidboss_respawn, between his fields, you will find this ones:
respawn_min_delay
respawn_max_delay
respawn_time
- respawn_time = the time (in millis) that raidboss will take to spawn after last kill
- respawn_min_delay = if this is greater than 0, the raid boss can respawn between respawn_time - respawn_min_delay and respawn_time
- respawn_max_delay = if this is greater than 0, the raid boss can respawn between respawn_time and respawn_time + respawn_max_delay
If both, respawn_min_delay and respawn_max_delay are greater than 0, the raid boss will spawn between respawn_time - respawn_min_delay and respawn_time + respawn_max_delay