do they stack? yes
temporal guard gives you minor protection..which is 8%
and potentates gives you a unique 5% resist buff vs players
as for how it adds together, idfk
also small note, major and minor buffs do not stack with copies of themselves
i.e. minor protection does NOT stack with another source of minor protection [temporal guard + templar jabs for example..two sources of MP but you'd still only get 8%]
however minor protection would stack with major protection..as they are two different buffs
Stack in the form if someone does 200 dmg its minus 50% for battlespirit makes is 100 then minor protection minus 8% making it 92 and so on. There all seperate calculations not stack in one big % mitigation.