Under the umbrella of Indian Knowledge Systems (IKS) division of All India Council for Technical Education (AICTE), Government of India, we target the problem of building general purpose knowledge graph from Sanskrit text of Vālmīki Rāmāyaṇa as well as building natural language question answering system on top of the constructed KG. Due to several limitations related to the state of the art of Sanskrit NLP for semantic tasks, we opt for the process of manual annotation. We have developed a comprehensive NLP annotation tool Antarlekhaka, which is being used for this large scale annotation task.