In this au tanjiro has been trained by his father tanjuro to use sun breathing.
Tanjiro can use sun breathing 12 forms without any backlash, he does not know the 13th form of sun breathing.
Another thing he looks a lot like yoriichi so muzan Jackson...
So about the power level of tanjiro he is close to the mugen train tanjiro of cannon also his demon Slayer mark looks like this
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But he has long hair like yoriichi tsugikuni but his mark is not complete demon Slayer mark.
Also he is naturally really strong like muichiro his personality is the same as the cannon.
Even without any training tanjiro can easily kill normal demons and a lower moon too so he is not op at the start but he is going to surpass hashiras in no time in the future.
Also in this timeline demon Slayer corps will know about sun breathing and about the earings of yoriichi and about how yoriichi almost killed muzan.
