In my experience, the chance for creatures to spawn at each of the 10 Lightbearer basins seems to be different and random. My server is Pacera and every year since the start we all do our part and help with the event, so I was grateful to stand at each basin for at least 2 hours each.
The basin with the lowest percentage for creatures to spawn according to my documentation was Plains of Havoc at 25% and the highest percentage for creatures to spawn was Tarpit Tombs at 76.47%. Sometimes it was hard to tell if the creatures spawned because of the previous player lighting the basin or not so I could imagine my calculations aren’t exactly on the mark, but I am confident I’m close to it. It also would've been helpful to have the same amount of lightings for each basin but trust me, looking at 10 lightings I do not see any similarities so the more results the better. It was a little hard because some basins were also lit more than others.
I was very detailed and realized day or night had nothing to do with any of the Lightbearer creatures, I cannot notice a pattern only that it seems to be a random chance that they spawn and the waves only spawn for 5 minutes if a wave was created. I noticed it seems each wave brings us 1-6 creatures if created. The creatures tend to not disappear if you don’t kill the waves so sometimes you could walk into a spawn filled with 20+ Lightbearer creatures let’s say if 3 people lit and walked away. Anywho, would be interesting to try this again on another event to compare my results but here is a chart based on my finding at each basin:
|Lightbearer Basin||Chance to spawn|
|Edron||65% or 13 out of 20 times the creatures spawned|
|Drefia||36.36% or 4 out of 11 times the creatures spawned|
|Tarpit Tomb||76.47% or 13 out of 17 times the creatures spawned|
|Hellgate||56.25% or 18 out of 32 times the creatures spawned|
|Svargrond||44,44% or 8 out of 11 times the creatures spawned|
|Kazordoon||41.94% or 13 out of 31 times the creatures spawned|
|Ramoa||33.33% or 4 out of 12 times the creatures spawned|
|Forbidden Islands||58.82% or 10 out of 17 times the creatures spawned|
|Plains of Havoc||25% or 4 out of 16 times the creatures spawned|
|Yalahar||46.15% or 6 out of 13 times the creatures spawned|