Sage Shuka, son of Sage Vyasa, is an important person in Mahabharata. It is Shuka who narrates Srimad Bhagavata to King Pareekshit. Moksha is a fascinating story in Mahabharata that elevates one to look at life with divine dispassion.
The larger goal of life must be renunciation and striving for Moksha. Nahusha rediscovers this emphasis for himself, eventually, in his conversation with Yudhishthira – in the discussion of who a genuine brahmana/sage is and the nature of the Parabrahma vastu. Thus, he sets himself firmly in the path of renunciation in the guidance he provides to the future that is Yudhishthira. Hence, he regains his divine form and the right to be back to the exalted worlds.
The story of the death of King Pareekshita is narrated in Adi Parva twice – once narrated by Sage Ugrashrava Souti to Shaunaka and once more by the ministers of Janamejaya to the king himself. This is a great story how our passion creates a prowess and the lust to demonstrate that prowess takes us in the wrong direction. The story goes thus.