So I have thought about this one possibility and felt like sharing with our community.
We know that Obscurus is a dark parasitic magical entity that could develop within a person if his/her magic is excessively suppressed and could inevitably burst out into calamities. What I am wondering is what if a person whom you truly love becomes an Obscurial under obvious circumstances be it your parent, sibling or spouse. When that person would die of being Obscurial, their incredible Obscurus power will be harboured within you who truly loved them.
Now if their Obscurus becomes an inseparable part of you, you will be granted the similar incredible power which you greatly lacked before the merge of Obscurus with you. The difference will be that you will not die of the Obscurus and would love normal lifetime. Also it will not go out of your control because it isn't originally your Obscurus. I think this should work because after the merge, still technically it is a parasite. This way you may get an incredible power as the legacy of your Obscurial deceased loved one. This also explains that your love for them was so strong that still a good part of them resides with and within you.
How do you like this? Please tell me.