In India, a registered document (including a will) can be challenged by any person whose rights, title or interest in the subject matter of the document is affected by the document which is under challenge.Therefore the general rule on who can challenge a document is that, those persons whose rights, title or interest are directly affected by the document can challenge the document. However the CPC provides an exceptions where even though a person is not directly affected, he can challenge the suit. As per Section 91 of the CPC, in cases where the impugned document would result in public nuisance or other wrongful act which would affect the public, a suit for declaration and injunction or other relief can be instituted with the leave of the court by at least two or more person. In this case, it is not required that these two or more persons have themselves suffered any special damage as a consequence of the document.
Registration of a deed merely requires the person executing the deed (executant) or any person claiming under it (claimant) or his legal representative to present the document at the proper Registration Office
At present the title is in your name so you are the absolute owner of the property. You can alienate the property as per your wish.