Interesting start. Painful what inu-papa did to Sesshomaru. ouch. That was just... really, really harsh to do to someone, especially a child. Especially one HE raised against emotions and happiness.
Some minor errors for which you might want to check and fix. I recall off-hand a 'to' that should be a 'too.' Little things like that.
Big thing though... this is clearly not a Canon fanfiction. If you can you should change it to Alternate.
I look forward to seeing where you take this.
Thanks for writing!