Matsya Purana — Paurava Genealogy: Bharata
विष्वक्सेनस्य पुत्रस्तु उदक्सेनो बभूव ह भल्लाटस्तस्य पुत्रस्तु तस्यासीज्जनमेजयः उग्रायुधेन तस्यार्थे सर्वे नीपाः प्रणाशिताः //
viṣvaksenasya putrastu udakseno babhūva ha bhallāṭastasya putrastu tasyāsījjanamejayaḥ ugrāyudhena tasyārthe sarve nīpāḥ praṇāśitāḥ //
Viṣvaksena’s son, it is said, was Udaksena. His son was Bhallāṭa, and Bhallāṭa’s son was Janamejaya. For his sake—by the warrior Ugrāyudha—all the Nīpa kings were destroyed.
Nothing directly—this verse is a genealogical notice, listing descendants and a dynastic destruction, not a Pralaya (cosmic dissolution) teaching.
Indirectly, it highlights the political stakes of kingship: dynasties rise and fall through alliances and warfare; a king’s dharma includes protecting the realm and avoiding actions that lead to total clan-destruction.
None is stated here; the verse belongs to vamśa (dynasty) narration rather than Matsya Purana Vastu Shastra tips or temple-building rules.