Terra..

I was re playing Kingdom hearts bbs and thinking that if the 13 darknesses and 7 lights clash at the keyblade graveyard wont the lingering sentiment ( will ) still be there to help the light side. he has a strong hatred for xehanort so once he senses him wont he go after him

 

This is a very good point! I didn't think of it! I haven't played KH3D yet, so unless that says otherwise, I do agree with you. I can't think of anything that would keep it from fighting alongside the 7 Lights.

 

But that's the thing: it's just a will. Will doesn't belong to or even contain either light or darkness unlike the heart and therefore it would not be of any use to Xehanort's plan of making the X-Blade. Yes, it can use a Keyblade and can probably utilize light in its attacks, but that's only because its a fragment of Terra.

That doesn't mean that if they ever clash at the Keyblade Graveyard the Lingering Will won't be able to help out, though.