BUR #16225 has been approved by @nonamethanks.
create alias master_1_(housamo) -> protagonist_1_(housamo)
create alias master_2_(housamo) -> protagonist_2_(housamo)
create alias master_3_(housamo) -> protagonist_3_(housamo)
create alias master_4_(housamo) -> protagonist_4_(housamo)
create alias master_5_(housamo) -> protagonist_5_(housamo)
create alias mc1_(housamo) -> protagonist_1_(housamo)
create alias mc2_(housamo) -> protagonist_2_(housamo)
create alias mc3_(housamo) -> protagonist_3_(housamo)
create alias mc4_(housamo) -> protagonist_4_(housamo)
create alias mc5_(housamo) -> protagonist_5_(housamo)
The word the game uses to refer to the main character is Shujinkō, and both wikis and fandom uses protagonist as translation.
https://housamo.wiki/Protagonist
https://housamo.fandom.com/wiki/Protagonist
In the actual fandom mc and protagonist seem like the more common ways used to call the characters. So these aliases should help discoverability.
Updated