How strong is the leader of the Demon Slayer Corps

Question

During Tanjiro's trial, the leader, also known as "Oyakata-Sama" was introduced and despite his weak appearance, I was quite surprised at how much respect he was able to command from all the pillars and this got me wandering how strong he is (or must've been in his prime).

He mentioned that the Hashiras only acknowledged strength. So this leads to my question, how powerful is "oyakata sama" comparatively to the upper Moons and how did he get the "Byakugan-like" curse on his face.

Also (just in case he was never a force to be reckoned with), why would someone so weak be chosen to be the head of such a powerful organization? and how was he able to tame the Hashiras.

Answer 1

A simple answer would be: He isn't all that strong. Any more would be a major spoiler so proceed with caution.

Not only is he "not that strong" he is pitifully weak. The reason he leads the demon slayer corps is because they follow him. Here's a bit on the history and powers of his family:

His lineage goes back to the time when the first demon was born. Muzan came from the same family and him becoming a demon cursed their bloodline, any child born into their family would not survive for long. They needed to kill the demon born in their family to lift the curse. They were given brides from the temple and it allowed their children to at least live till their twenties. Since then their family has been raising the demon slayer corps. The only benefit they got from all this has been an heightened intuition, one that was almost clairvoyant. Through that they have evaded countless disasters, amassed great wealth and made critical guesses on situations that would be otheriwse impossible(such that Muzan can't be killed with demon slayer swords)

Their family has been doing this for countless years all to defeat Muzan, and demon slayers have been following them.

Coming to the other part of your question:

Hashiras do value strength and they are eccentric weirdos but they aren't brainless brutes. All of them are plenty smart. They realise that Ubuyashiki Kagaya (Oyakata-Sama) is a man worthy to be thier lord. Ubuyashiki is a man who truly cares for all demon slayers, if giving away his life would be any useful, then he would happily do so. He's tactful and wise at the same time humble and kind. He is saddened whenever a slayer dies and remembers the name and background of each demon slayer in the corps. His eyes have gone blind, skin is rotting and his end is not far, but regardless the only aim of his life is to slay muzan. He demands no respect or submission from pillars and they all follow him on their own accord.

There are demon slayers who want to climb ranks to earn money and fame, but we haven't seen any of them go far. It has been mentioned by Gyomei (Stone Pillar) that the most promising and hardworking demon slayers come from families destoyed by demons and from households who have been slaying demons thourgh generations. That might be one reason why all hashiras have turned out like this (not to mention if the top tiers are like this the lower ranked slayers will naturally follow them)