Let's all try to calculate the length of Tesilid's life stages together! 🤔
Here's a non-exhaustive list of information I have so far / assumptions we have to make:
Let's count the ages of OG!Tesilid (without Ailette, before Voice recreated the world) and Current!Tesilid separately. A lot of the estimates given on Tesilid's current age is also based on only the age of his VoiceWorldEra and doesn't count the time his soul spent in Strict Order's original world
Current!Tesilid is about 7000 years old. (Source: this probably non-canon fun snippet that Irinbi posted on twitter)
His age is around 4 figures (Source: some chapter related to carteleya)
Info relating to the save files/abyss
Each save file can last 10k years. Muriel has 10 of them
Each save file has 30 saves, which puts each save at a maximum of about 333.33 years
Current!Tesilid spent 15 full saves and part of the 16th save in the abyss before Ailette saved him, which puts him at having spent a maximum of 5,333.33 years in the abyss in his current iteration
This means he probably spent a ballpark figure of 7000 - 5333 = 1667 years as a human before being sealed as Reed
iirc Reed spent a few hundred years in some subspace learning magic before he started trying to kill his younger self, so that puts his life actually spent like a human as closer to 1000 than 1500.
Calculating the age of his sould
Voice has stated before that the souls were the only things that are the same as when Strict Order was in charge. Which means that Tesilid's soul should be the same, even if he doesn't remember it and even if he/Carteleya's Eyes doesn't count the age of his soul in Strict Order's save file
Voice says that (1) if Tesilid had spent 10,000 years in the abyss, he would've ascended godhood, and (2) Tesilid was pretty close to it already as-is
If we take 5333 years from his Voice!era, that puts him at a maximum of about 4667 years spent in the abyss before Voice took over. Damn, that's shorter than the amount of time it took before Ailette saved him. That's harsh. What was Voice even going to do if Merchant didn't help Ailette save him? Just let him ascend to godhood? Time in the abyss doesn't flow the same way as Ailette's timeline, so could God!Tesilid feasibly have found his way to Ailette? What was Voice gonna do if Tesilid tries to poach her?!?!??
It could also be that Voice just sucked all the divinity out of Tesilid before loading him into the new world, which effectively reset his age to zero. Tbh. So Tesilid could have spent up to 9999 years in Strict Order's abyss.
TLDR timeline of current!Tesilid's life:
0 to 20: Get lightly screwed over by the Vatican
~several hundred years: train and learn magic in the subspace or whatever that is
~1 to 2 years: Wreck havoc in Round 17
Around 1600 y/o to around 7000 y/o: Get fucked (spend at most 5333 years in the abyss)
If you want to get the breakdown for OG!Tesilid's life, just swap Pt 5 so that he spends between 4667 to 9999 years before Voice picks him up.
Man. His life really sucks, huh.