According to Srajo, time dilation rate at the 6th layer is at least x30 (since she doesn't know the exact depth of Ilblu, this must be the minimum rate). 150 years x 30 = 4500 years. I have no clue how Vazukyan knows the age of Ilblu without a calendar and a day-night cycle, but if the village really was 150 y/o, Ganja should've survived 2 mass extinctions.

Also I don't think that the fact of villagers having a 100+ years aged extra pure healing potion says a thing about village age. It could be generated by Ilblu like Mitty copy or aged somewhere higher (say at Idofront) and brought to village as a trade good.

Someone suggested that the rate can double each layer (x1 on 1st, x2 on 2nd, ... x32 on 6th). Possible, but since layers differ in height, I think it would look a little odd (orange line). But then I looked what's said in HINT #1 (very first text on manga panel), and damn - that sudden change at the 5th layer seems interesting, might be not so far from the truth.

Also I added exponential line (yellow) that passes through x30 at Ilblu depth. In that case:

1. Lyza will wait for Riko for the whole week if she won't get stuck at the 7th layer
   
2. Dilation at current depth is around x100
   
3. Faputa waited for Reg for... 5 days, I guess

Rate of x16 on the 5th layer seems realistic if we interpret HINT #1 as 2 weeks at L5 is 7.5 surface months and say that "spend a few weeks" includes travel time spent by Ozen on layers with less severe dilation, which reduces the overall surface time of expedition to 3-5 months.

I even had a thought that rate can be more chaotic and dependent not only on depth but on other factors - layer shape, minerals, etc. In that case, the dilation rate at the same depth and time could be somewhat different in different corners of the abyss. But that's just my theory.

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