Board Thread:Wiki Discussions and Support/@comment-25369463-20141101085056/@comment-25028454-20141101130812

Usually when someone seal something their have to be some kind sign somewhere to trap whatever it is in that seal. Absorbing you can "borrow" its power once it's sealed away in you or elsewhere. Naruto for example the Kyubi is sealed away within him and he can also absorb a small to big portion of it's power to use as he sees fit at least that's how I think of it.