The Drath Series: Book 4-6. The Drath Series, #23

Ranging around him, finding his memory meant certain execution. Not finding it might mean the downfall of galactic civilization. Then, in Stranded With You, Min-Su Truman is stranded after the interstellar comms went down. All space liner traffic was cancelled indefinitely. Finding a way home meant dealing with stolen hotel rooms, clone sisters with bombs and collapsed governments. As well as the Drathanni and falling in love.
Finally, in Reunited Hearts, Hasenkamp's entire world has collapsed around him. His criminal empire has fallen. His world's government has been overturned. There is no place left for him on Melin. Finding a new place for himself and his people meant touching base with rival gang lords and reconnecting with the love he'd thought long gone. This collects the second three books of the Drath series: Fragments of a Chain, Stranded With You, and Reunited Hearts.