Raja Ghepan, the presiding lord of Lahaul, resides on Ghepan (Gepang) mountain, which towers above Sissu, 4km west of the Rohtang Tunnel's northern entrance. In Sissu village his architecturally forgettable temple looks like a modern house with vihara tacked on, but it's of great local significance spiritually.
You can climb the steps to peer through a grille at a mound of cloths covering the deity's holy artefacts.