After you defeat Baal, Commander Tapps will appear again at Level 5001 and cheer you:

Tapps: "Aha! That showed him! Master no more! The birds sing! The monsters have fled. Peace is upon the land. At the Edge of Infinity the guardians rejoice, the heavens ring with their cheers. I think it's time to put up my boots and look forward to a quiet sun. Or ... What do you say, one last sparring round?"