Master
A “master” often refers to the original or main version of an entity. Webmaster, Scrum Master, Flow Master, Master Branch
Why it matters
Considerations for gendered stereotypes of man and master being superior to others, as well as the associated link to 'slave' used as an oppressive metaphor (see entry: Master / Slave)
Instead try saying:
Manager/Expert/Facilitator/Lead
Further External Reading Link