Amaterasu has a title called Date Masamune which brings up my Oodachi Aff 60%.....But it says I must have Kagahide in my possession. Um what exactly is that I can't find it on Wiki

It is an Odachi (level 55~ if I recall), and it drops in the dungeons/fields in Sekigahara and Nether Sekigahara. You will need to +60 one to get the title.

TY TY MUCH GOOD SIR