Usualy in light novels, the MC is a loner or a leader that don’t want to take a side, so i’m looking for à light novel where the MC(male or female) is willingly serving/working for someone, not necesseraly stronger and have a geniuinly friendly relationship with his/her master. The MC can be a buttler/maid, a subordinate, an apostle, a pet etc. The master can be a king, a demon lord, a god or a rich person etc. I have only read a few light novel like this. For exemple: Kumo desu ga nani ka, Transmigrated as a ghost, or the begining of The Legendary Mechanic.