I searched the Incomplete Romance list and did not see any Deseru/Dazuru (Heath/Keith) on there anywhere. Honestly, I'm surprised.
Deseru freaking tied up Dazuru and kept him on his helicopter until the player came to rescue him, what more do you want?!
I propose DesertGemShipping, because the two of them were both in the desert temple searching for the Yellow Gem and that's why Deseru kidnapped Daz in the first place.
(I was going to suggest "VoicemailShipping" because Deseru uses Daz's voicemail to lure the player to the desert but then I found out it's the ship name for Hajime/Rhythmi already, so...)